Home

Manual - Siborg Systems Inc.

1. 78 H LE Bleclrodes dea 78 38V D IV data or aset of IV CUrVes sc ceca bee nre e ren 78 MAT Material PropertiesS 78 MOB MobilitymodelS nmanannana 79 REC Recombination parameters annnan 79 M P Impact ionization die serena m PM tee dea YR oe E C e Pee et 79 PHO Photogenerallon en IA ete Rocket Ue aks 79 6 6 2 BAS Basic directivesS 79 MESH Domain and mesh parameterS n 80 SOLV Computation control uuu kdo b e e oie v e bebes 80 MODEM odel options ratico ar reat dee ard c a Pct She ona airs 81 6 6 3 DOP Analytical doping data 81 DOPA Doping Wellies y Vue aut se Cre opt ien ot eo aro ES a 39e 81 DOPN Numerical dopingdata 82 6 64 HOX OXE is cec O 82 QUID PSOE regi n asp doen ade s Age Doi ra boats HALE Ao CE kia de 82 6 5 5 PREM Remesi cera reti ECCE EY died 83 REM E Remesh FeglOT ses oes mean ls 83 6 6 6 ELE Electrodedirective 83 OHMI Ohmicelectrode 83 GATE Gate electrode cute iere Pe IA WA 84 SCHO Schottky electrode 84 MICROTEC 4 0 User s M anual 6 6 7 VD IV datadirective
2. 85 MDA ICUS ia 5 ost A A 85 6 6 8 AMAT Material propertiesS sas 85 BAND Temperature and bandgap parameters 85 PERM Dielectric pei a ai Meebo wee cate ae eee eee ed 86 WORK Semiconductor work function 87 6 6 9 MOB Mobility modelS anananan 87 CONM Constant mobility model 87 YAMA Yamaguchi mobility model 87 LOM B Lombardi surface mobility model 88 BIPO Bipolar mobility model 90 6 6 10 REC Recombination parameters 0 cc ec cece eee teens 92 SRH Shockley Read H all recombination parameters 92 AUGE Auger recombination parameters 93 SURF Surface recombination parameters 93 RADI Radiative recombination parametefs 94 6 6 11 MP ImpactiIOnization wanaaanwaaan 94 IONE Impact ionization exponent snaamwanan 94 IONP Impactionizationcoefficient 95 6 6 12 PHO Photogeneration wwaaan 96 PHOT Photogeneration Well n 96 MICROTEC 4 0 User s M anual GETTING STARTED MICROTEC 4 0 User s M anua 7 Chapter 1 Get
3. where C isthe concentration of the k th impurity D is the diffusivity Z is the charge number uw is the electrical mobility g is the elementary charge and is the electric field This model uses the quasineutral approximation which relates the electric field to impurity concentrations py Eine 4 2 where MICROTEC 4 0 User s M anual 35 Process Simulation Chapter 4 2 n Apacer yc en 43 k k Here n is the electron concentration and n is the intrinsic carrier concentration hj fig T exp 574 44 From 2 and 3 we obtain E KT q E Y ZINC 4 5 xz 4n k Zq Assuming that the Einstein relation u Ar Pk is valid the diffusion equation transforms to ZV Cy Ji 0 VC Z 4 6 2 k In the case of one impurity the drift can be taken into account by introducing a multiplicative factor for the diffusivity 3 but for several impurities the following system of coupled equations must be solved 2s YZNC V ONC 02Z 6 4 7 ot 2 k 4 2 1 Diffusion coefficient The diffusivity of arsenic and boron accounting for single charged defect influence is chosen in 36 MICROTEC 4 0 User s M anual Chapter 4 Process Simulation the form 3 4 5 E T 4 1 D Doxere Fr 5 B where n for arsenic n E for boron Do and Eo are the intrinsic diffusion coefficient i i and activation energy of the k th impurity respectively The parameter
4. AY tA p i a IA infinity piecewise coefficients Symbol Name Default Units Description Eo ENO 10 0 V cm Electric field range 0 Ey for electrons Ez EN1 40 102 V cm Electric field range Eg E for electrons E EN2 6010 V cm Electric field range E E for electrons b BNO 0 0 V cm Field exponent for electrons in 0 Eg o BN1 14109 V cm Field exponent for electrons in Eg Ey 94 MICROTEC 4 0 User s M anual Chapter 6 Device Simulation Symbol Name Default Units Description p BN2 14 106 V cm Field exponent for electrons in E Ez e BN3 14 106 V cm Field exponent for electrons in E Eo EPO 0 0 V cm Electric field range for holes Ez EPI 6 07109 V cm Electric field range for holes E gt EP2 6 07109 V cm Electric field range for holes b BPO 0 0 V cm Field exponent for holes in 0 Eg bl BP1 2 0910 V cm Field exponent for holes in Eg Ex bp BP2 14 106 V cm Field exponent for holes in E4 E b BP3 14 106 V cm Field exponent for holes in E a ANO 0 0 1 cm loniz coef for elect in range 0 Eg IONP Impact ionization coefficient Symbol Name Default Units D escription a ANO 0 0 1 cm loniz coef for elect in range 0 Eg a ANI 7010 l em loniz coef for elect in range Eg Ex YA AN2 7010 1 cm loniz coef
5. there is an item called Directives This item allows you to create directives in the window in which you arein Directives are sections of the graph which refer to specific sections listed in the project settings tab of the main window You may change the directives in the SibGraf Edit win dow by Once you change the directives in the SibGraf Edit window and restart the program 30 MICROTEC 4 0 User s M anual Chapter 3 M icroT ec Graphics SibGraf pa ra or the directives will also change in the corresponding Sib Graf Map window To change the directives without TE GE Cancel Pre eghonesiial tacior DMMP for Pros ponies omes Figure 3 11 using the SibGraf Edit window simply go into the main window into the Project Settings tab there underneath the Project Tree you will find a list of names for the dif ferent directives Double click on the directive you wish to change and a wiimtow willl gup up where you can edit the directives by changing the number in the top box at press OK see diagram above MICROTEC 4 0 User s M anual 31 M icroT ec Graphics SibGraf Chapter 3 32 MICROTEC 4 0 User s M anual 4 PROCESS SIMULATION MICROTEC 4 0 User s M anua 33 Chapter 4 Process Simulation 4 1 Introduction It is well known that analytical approximations for doping profiles typically do not adequately reflect results of fabrication processing especially for devices with submicron dimensions A pr
6. 25x25 and twice as large time step The difference in position of the contour lines for both calculations was less than 0 01 microns in the region of the p n junction In the regions with concentration values of 10 4 10 5 cm the difference was 0 02 0 03 microns Thus the important parameter p n junction depth is determined with an accuracy sufficiently high 2 for an l V curve evaluation 4 4 References 1 M S Obrecht A L Alexandrov SIDIF a program for two dimensional modelling of diffu sion and oxidation Solid State Electronics Software Survey Section v 34 No 8 1991 40 MICROTEC 4 0 User s M anual Chapter 4 Process Simulation 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 A L Alexandrov M S Obrecht G V Gadiyak Efficient finite difference method for numer ical modelling of thermal redistribution of interacting impurities under oxidizing ambient Solid State Electronics v 35 p 1549 1552 1992 Process and Device Simulation for M OS VLSI Circuits Ed by P Antognetti R W D utton et al Martinus Nijhoff Publishers 1983 R W Dutton and D A Antoniadis M odels for computer simulation of complete IC fabrica tion processes IEEE Trans Electr Dev v ED 26 p 490 1979 C D Maldonado ROMANS Il A two dimensional process simulator Appl Phys vol A31 p 119 1983 R W Dutton C P Ho etal VLSI proces
7. G surf where Vp Vsp are recombination velocities for electrons and holes p 6 2 4 Boundary Conditions A few types of boundary conditions are available in SiM OS and BiSim At ideal Ohmic contacts the following conditions are imposed assuming infinite recombination rate for electrons and holes ny N74 mo Ny 2 6 18 MICROTEC 4 0 User s M anual 67 Device Simulation Chapter 6 0 fMy 4 Nata 6 19 z KT Ce Vo 5 V 6 20 where Vy Np N isthe net doping concentration and V is the k th contact voltage On the surface of Schottky contacts BiSim only carrier concentrations are defined by the following relations lay GVsp n Neg 6 21 I py QVs p Peg 6 22 Wo 7 Ogt V 6 23 where o is the difference of the intrinsic semiconductor and metal workfunctions v denotes current density component normal to the interface and equilibrium concentrations Neg Peg ate q Neg n exp 55 6 24 q Peg nex 2 625 On insulating segments of the boundary for current densities we have Jg REO cp 6 26 J pv Q R O surf 6 27 For normal components of electric field according to the Gauss theorem we have at the interface NEL 2 0ss 6 28 1 v 68 MICROTEC 4 0 User s M anual Chapter 6 Device Simulation where 4 e are dielectric permittivities of the respective materials and Q is a fixed surface charge density For open segments of the boundary E equal
8. Tool bar Status bar AutoR edraw allows you to make the toolbar and status bar visible or invisible Turn auto redraw on and off With autoredraw on the window will redraw itself auto matically once a window covering it is moved Redraw Redraw current surface Zoom Out Turns off zoom can also be done with ESC key Annotate See the Section A nnotate on page 30 Help Index Open a window with the help index A bout Display SibGraf info 3D Status Bar The status bar is the strip at the bottom of the plot window If probe mode is off the first row of three numbers in the status bar show the values of the X and Y coordinates of the current cross sections and the Z value at the point of their intersection If probe mode see below is on the first row of three numbers show the values of the X Y and Z coordinates at the current mouse position The bottom row of numbers always show the mesh step numbers of the current X and Y cross sections and the overall dimension of the grid 3D Tool Bar Thetool bar is the line of buttons just below the main menu and above the plot window The first four buttons are used to rotate the surface about horizontal and vertical axes associated with the screen The next four buttons are used to select different X and Y cross sections This can also be done by using the arrow keys on the keyboard The button L og Z is used to switch to and from a logarithmic scale Thethird last butt
9. s M anual Chapter 5 4 Examples of M ergIC inputfile 61 5 4 Te Viewing a fragmentis i va t9 eaput deese AE ibe he i Ud 61 5 4 2 Symmetrical device usingonefragment 61 5 4 3 Vertical BJT with substrate collector 61 5 4 4 Vertical BJT withaburiedlayer 62 SASA A AA WA AA AT E 62 6 DEVICE SIMUL ON IA KIWA ds OS Aa 63 6 1 Introducti Oise a A PRO Ko eter seus wie taeda YA 65 6 2 Basic System of EgGUatiONS wmemawwwwwwwwanana 65 6 2 aly Ba dgap Mao wingi obo teier rase eero e e a e aa a dn 65 6 2 2 SRH and Auger Recombination and Impact lonization 66 6 2 3 Surface Recombination sasssa 67 6 2 4 Boundary Conditions 2 a ec Ai 67 6 2 5 Mobility Motels A So e te e Reb a kha 69 6 3 Numerical UN seo op betas E P XR be teddy HR E Teo S 10 6 3 1 Finite Difference SCHEME uo lied 71 6 3 2 M odified linearization of the discretized Poisson equation 13 6 3 3 Initial guess Strategy s nosti trant rs ya ctr aci race ae e ots Sa 74 GA E AME DAL UY MIRO ee 76 6 5 RUNNING SEMSHM count tata de ae D eon eh Ea dad D e 77 b 6 Senis TTI DUETO e WA ots uM bee ety Yet A UA e 78 6 6 1 SemSim list of directives ui a o ee des ed 78 BAS BasicdirectiveS wannna 78 DOP Analytical dopingdata
10. 2 pp 134 142 1972 L N Lie R R Razouk and B E Deal High Pressure Oxidation of Silicon in Dry Oxygen J Electrochem Soc vol 129 No 12 pp 2828 2834 1982 R R Razouk L N Lie and B E Deal Kinetics of High Pressure Oxidation of Silicon in Pyrogenic Steam J Electrochem Soc vol 128 No 10 pp 2214 2220 1981 MICROTEC 4 0 User s M anual 41 Process Simulation Chapter 4 4 5 Running SiDif To run SiDif from the MicroTec shell select a SiDif project in the project list on the Select Project page and click Run in the main M icroT ec menu Y ou may also A dd Update Copy and or Delete projects in the main menu If you wantto modify a project click on Copy button A new project will be created with the old project name and copy at the end A fter that you may change the project settings by clicking on the Project Settings page tag This will display directives in the input file Double click on a directive unfolds it and lets you edit the parameters If you want to start a new project type the project name in the Name window select SiDif in the M ethod window and click Add A new project will be created with default parameter settings On the output SiDif generates a doping data file which may be directly used in the device simulation This output file also may be used by M ergl C to produce a more complex final device structure by copying overla
11. B defaults to 3 for boron and 100 for arsenic The phosphorus diffusivity was chosen as in 5 6 and accounts for the diffusion via neutral and single and double negatively charged vacancies Dp Dyexo 2 0 2 D exo E 07 Ji exp 72 4 2 4 2 2 Oxidation enhanced diffusion The diffusivity during oxidation is modified depending on the rate of oxidation in order to describe the oxidation enhanced or oxidation retarded diffusion 8 Oxidation changes the diffusivity because it generates interstitials in the crystalline lattice In SiDif the Taniguchi model is used 8 De 0 1502 He 41 The diffusivity enhancement decays exponentially in the above formula where Ax is the distance from the mask edge Ax 0 outside the masked region and y is the vertical distance from the interface 8 4 2 3 Analytical oxidation model For the analytical oxidation model the D eal Grove formulation is used 7 in SiDif dU 8B 4 1 where U is the oxide thickness and A B are kinetic constants which are proportional to the pressure and depend on the ambient composition The values A B are significantly higher if the MICROTEC 4 0 User s M anual 37 Process Simulation Chapter 4 ambient contains water vapor or HCI In the latter case the constants are given by 16 17 B PB exe E 2 P OR P erro exp 2 4 2 Here P isthe pressure of the oxidizing ambient in atmospheres and P pis the effective pressure
12. EA e c Aet d 4 8 SiDif model parameter directiveS BAND Bandgap and intrinsic carrier concentration DIFF Diffusivity of Arsenic Boron and Phosphorus OED Oxidation enhanced diffusion 4 8 1 Deal Grove oxidation kinetic constants 0 ccc cece eese DROX Dry oxidation Kinetic constants WEOX Wet oxidation kinetic constants cece cece eee ence eens LOCO Local oxidation bird s beak formula parameters SEGR Segregation Palameters a ees be ia CE YES 4 9 Examples of SiDifinputfiles 49T MOSFET fragment aies i cave KA a aod on ain 4 9 2 LDD MOSFET fragment ede 1m t rr P mte e Euer d 4 9 3 Fragment with LOCOS o osse ene oe eb ae ap n E bu 3 s 4 9 4 Doping by deposit Ofi s de E Rau AE Y Ee ead oY ES 4 9 5 Buried layer and Cp tanya s sees eva Fai eR pz ic OR Pee 4 0 6 Emiter Tegi ON ocn sapin dod rd hoo tie MIWA MABA CHI MAU MAU WALE We oA a 5 Device formaton ia oca ca e exacti SiN eed pede bekesa i decide des 5 T Introduction qois eo p bb m ebat orici plate eter c ones ded 5 2 POURING Merle Mier C IDnDUE M O 63 cte eta cba bl eo eee eats bee 5 3 1 MESH Domain and mesh 2 scutes tea Mia cete raa eoa ace e n Set 5 3 2 FRAG fragment description 4 MICROTEC 4 0 User
13. Properties BAND Temperature and bandgap 78 MICROTEC 4 0 User s M anual Chapter 6 Device Simulation PERM Dielectric permittivity WORK Workfunction 3M OB Mobility models CONM Constant mobility YAM A Yamaguchi mobility LOMB Lombardi mobility BIPO Bipolar mobility ZR EC Recombination parameters SRH Shockley R ead H all recombination parameters AUGE Auger recombination parameters SURF Surface recombination RADI Radiative recombination 34M P Impact ionization ONE Impact ionization exponents ONP Impact ionization coefficients P HO Photogeneration PHOT Photogeneration well 6 6 10 4BAS Basic directives This directive includes the following three unique directives M ESH SOLV and M ODE MICROTEC 4 0 User s M anual 79 Device Simulation Chapter 6 MESH Domain and mesh parameters Name Default Units Description NX 30 none Number of mesh nodes in X direction along the wafer sur face It must be greater than 3 A greater number of mesh nodes gives a higher computational accuracy at the expense of alarger CPU time NY 30 none Number of mesh nodes in Y direction into the depth of the wafer It must be greater than 3 XX 1 um Domain size in X direction microns YY 1 um Domain size in Y direction ZZ 1 um Domain size in Z direction in other words device width HYO 0 01 um Y direction first step size used only if IM ESH is
14. Solid State Electronics Software Survey Section vol 34 No 7 1991 3 M S Obrecht A new stable method for linearization of discretized basic semiconductor equations Solid State Electronics vol 36 No 4 pp 643 648 1993 4 M S Obrecht and M I Elmasry Speeding up of convergence of Gummel iterations for transient simulation Proceedings of the Ninth International Conference on the Numerical Analysis of Semiconductor Devices and Integrated Circuits Copper M ountains CO April 6 8 1993 Front Range Press pp 20 21 5 M S Obrecht and M I Elmasry Speeding up of convergence of Gummel iterations for transient simulation COM PEL v 12 pp 311 317 6 J V Slotboom and H C De Graaf M easurements of bandgap narrowing in silicon bipolar transistor Solid State Electronics vol 19 pp 857 862 1976 7 A G Chynoweth lonization rates for electrons and holes in silicon Phys Rev vol 109 pp 1537 1540 1958 76 MICROTEC 4 0 User s M anual Chapter 6 Device Simulation 8 D M Caughey and R E Thomas Carrier mobilities in silicon semi empirically related to temperature doping and injection level Proc IEEE vol 55 pp 2192 2193 1967 9 K Yamaguchi A mobility model for carriers in the MOS inversion layer IEEE Trans Electron Devices vol 30 pp 658 663 1983 10 C Lombardi S M anzini A Saporito and M Vanzi A physically based mobility model for numerical simulation of n
15. TCP 950 0 ye Parabolic constant critical temperature for wet O3 B BW1 4 722 um s Parabolic oxidation rate constant in wet O5 for T T Eg BWE1 1 17 eV Parabolic activation energy in wet O5 for T T B BW2 0 1167 um s Parabolic oxidation rate constant in wet O5 for T T Eg BWE2 0 78 eV Parabolic activation energy in wet O5 for T T i TEL 900 0 C Linear constant critical temperature for wet O3 Ro BAW1 575 0 um s Linear oxidation rate constant in wet O5 for T T Es BAWE1 1 6 eV Linear oxidation activation energy in wet O for T lt Tc R BAW2 4 917 104 um2 s Linear oxidation rate constant in wet O5 for T gt T Ep BAWE2 2 05 eV Linear oxidation activation energy in wet O for T gt Tc 50 MICROTEC 4 0 User s M anual Chapter 4 Process Simulation LOCO Local oxidation bird s beak formula parameters E U Up X XM U x Uy A 59 8 7 8 In Up 5 123 65 64 T 05x U 1 T Pass 3 Ya 7 5x UCD Symbol Name Default Units Description X KHIO 0 0 um The K appa for 100 orientation for bird s beak X KHI1 1 0 um The K appa for 111 orientation for bird s beak 8g DELO 0 97 um The first coefficient in Delta for bird s beak 84 DEL1 6 0e 4 um The second coefficient in Delta for bird s beak 8 DEL2 0 034 um The third coefficient in Delta for bird s beak 53 DEL3 0 49 um The forth coefficient in Delta for bird s be
16. by the following formulae T A ua T 2 Ez 6 35 t poe 3 Et u N T fixe eM DO A PE 6 36 T TC rst 5 where Larry SEU and ps a t The basic parameters in the above expressions are user defined 6 3 Numerical technique A finite difference technique on a rectangular grid is used together with a decoupled method of iterating over the non linearity the so called Gummel iteration For discretization of the continuity equations we use the conventional Scharfetter G ummel approximation 11 Conjugate gradient methods with preconditioning 12 13 are available for solving the linear systems We transform to dimensionless variables 15 X n Vnew X Xnew iones 2 6 37 where p is the intrinsic Debye length Retaining the old notation for the new dimensionless variables we obtain 70 MICROTEC 4 0 User s M anual Chapter 6 Device Simulation V2y n p No Na 6 38 VJn R 6 6 39 VJ R G 6 40 6 3 6 Finite Difference Scheme In the two dimensional case standard discretization of 4 6 using a central difference scheme for the Poisson equation and the Scharfetter Gummel approximation 11 for the current densities gives see e g 15 Crh AEPECNW j POW j a Np Ma Ej 6 41 An j h r R O 6 42 AMA j AErE R O 6 43 The subscripts j number the grid nodes A x x and r 741 1 are the sizes of the space steps t is the time s
17. choices File Plot View Annotate and Help The subtopics available under these menus are described below File Open Open a file containing a plot previously created 85 and saved by this program mtm Load Load data from a file containing 2D distribution data 3d Save Save the plot to the picture file that is currently open If there is no plot that is currently open if the Load function was used instead then this function will behave as the Save As function described below mtm Save As Save the plot to a picture file A window will be provided to allow you to choose the file name Clear Erase the plot that is currently in the plot window Print Print the plot that is currently in the plot window to a printer or to a PostScript file au eae Figure 3 7 SibGraf map window Export Data Allows you transfer information from Sib Graf M ap into another file Import Data Allows you to add information to the SibGraf M ap window New Window Open a new empty SibGraf M ap window Exit Close the window Plot Source Opens a window which shows the data source for Liapirs canceabalian jon 31 the current plot Select Allows you to chose a variable to add to the SibGraf M ap window from a list of given variables See figure 3 8 If the current plot was invoked through the Open function Polson cocida sl a J Sourc
18. contact to sweep the voltage NPNT 1 none Number of IV points to be evaluated VSTE 0 1 V Voltage step size VI 0 V Initial voltage for contact 1 V2 0 V Initial voltage for contact 2 V3 V20 0 V Same as above just a repetition Initial voltage for a contact 3 20 M aximum contact number is equal to 20 6 6 16 M AT Material properties This directive contains three unique subdirectives BAND PERM and WORK BAND Temperature and bandgap parameters MICROTEC 4 0 User s M anual 85 Device Simulation Chapter 6 1 mtir toro Ma ra 2 2 300 T EXT E E RN vd sete EA E T 3 2 ii T 3 2 NAT NeG00 5 NAT NyG00 77 Symbol Name Default Units Description T TEMP 300 K Temperature E 300 EG30 1 08 eV B andgap width at 300 K m EGAL 4 73104 eV Value of A Ipha in the formula for the bandgap width Egg EGBE 63610 K Temperature correction term in the for mula for the bandgap width N 300 ENC3 2 8 1019 cm3 The semiconductor conduction band den sity of states N 300 ENV3 1 041019 cm3 The semiconductor valence band density of states Vipan VOBG 0 009 eV The voltage parameter in the bandgap nar rowing model No BGN CONB 1 010 cm3 The concentration parameter in the band gap narrowing model Caan CNSB 0 5 none The constant parameter in the bandgap narrowing model PERM Dielectric permittivity Nam
19. equal to 0 M ESH 2 none If MESH 0 the mesh size is constantin X direction and expo nentially growing in Y direction If M ESH 1 mesh data are to be read from file If M ESH 2 automatic remeshing is per formed in both X and Y directions If M ESH 23 or 4 remesh ing is done only for X or Y directions respectively SOLV Computation control Name Default Units Description COMM Comm none Comment line to be written in the output file BATC 1 none If BATC 1 simulate without interactive plotting after every IV point if BATC 0 otherwise GUMM 100 none Number of Gummel iterations for closure Iteration stops when either the Gummel residual or the maximum number of Gummel iteration has been reached GRES 0 01 kT q Gummel residual criterion for closure Iteration stops when either the Gummel residual or the maximum number of Gum mel iteration has been reached 80 MICROTEC 4 0 User s M anual Chapter 6 Device Simulation MODE M odel options Name Default Units Description ELHL 0 none Solve continuity equations for both carriers if ELHL 0 Solve for electrons or holes only if ELHL is equal 1 or 2 respec tively HVDO 1 none UseSlotboom heavy doping bandgap narrowing model if HVDO 1 and otherwise if HV DO 0 IMPI 0 none Use Chinoweth impact ionization model if IM PI 1 and other wise if IM PI 0
20. for elect in range E4 E a AN3 17010 l cm loniz coef for elect in range E gt a APO 0 0 1 cm loniz coef for holes in range 0 Eg at AP1 1 3106 l cm loniz coef for holes in range Eg Ey al AP2 4 4109 l cm loniz coef for holes in range E E ap AP3 4 4108 l cm loniz coef for holes in range E infinity MICROTEC 4 0 User s M anual 95 Device Simulation Chapter 6 6 6 20 P HO Photogeneration This directive may include any number of PHOT subdirectives The photogeneration distribution is described by a superposition of photogeneration wells Each well is defined by one PHOT subdirective similar to the analytical doping profile using subdirective DOPA PHOT Photogener ation well Name Default Units Description RATE 1102 cm3 s Maximum photogeneration rate in the well XLFT 0 um Left edge of the doping well XRGT 1 um Right edge of the doping well Y TOP 0 um Top of the doping well Y BOT 1 um Bottom of the doping well ALX 0 001 um Characteristic length in X direction ALY 0 001 um Characteristic length in Y direction 6 6 21 OKI Oxide region This directive may include up to 20 OXID subdirectives Each rectangular region is defined by one OXID subdirective OXID Oxide region Name Default Units Description COMM Name none Region description PERM 3 8 no units Oxide permittivity XOXL 0 um L
21. icroT ec Graphics SibGraf Chapter 3 Import Data Allows you to add new data from a file to the graph The file may contain a few curves For every curve the first line for every subset of data includes the number of points in the curve and name of the curve followed by two columns of data for X and Y axis respectively Export Data Allows you to transfer data from the graph into an A SCII file See previous section for the file format The file can then be imported using the Import D ata command New Window Open new empty Sibgraf 2D window Exit Close the window Plot Add Open a window which displays the information about the current data file A file must have been previously loaded with the Load command under the File submenu for this to work A new window appears showing the information extracted from the data file which has been loaded It enables the user to select curves to be shown in the plot window The data labels are derived by appending the first letters of the Electrode name parameters to the predefined letters V for volt age and for current The first line of this window shows the current family number and name and allows the user to switch between families Odd family numbers correspond to IV data and even numbers correspond to transconduc tance data The table contains names as well as maxi mum and minimum values of each column in the current family The first two check boxes beside each
22. icroTec does not handle non planar structures a planarization of the doping profiles is made in M ergl C Therefore vertical doping profiles generated by SiDif are shifted vertically so as to align the Si SiO interface with the line y 0 At the same time the impurity concentration values at y locations beyond the original domain generated by SiDif are filled with the value of the last point available i e the bottom impurity concentration value in the SiDif output file 5 3 MerglC input file e Each directive starts a group of parameters separated by spaces or commas and ended by Each FRAG directive must be ended by The last directive must be ended by All directives after will be ignored MICROTEC 4 0 User s M anual 59 Device formation Chapter 5 5 3 1 MESH Domain and mesh Name Default Units Description NX N umber of nodes in X direction along the surface it must be greater than 3 NY Number of nodes in Y direction into the depth of the domain It must be greater than 3 The number of nodes affects accuracy and disk space required for the output file XX Device size in X direction um YY Device size in Y direction um COMM Comm none Comment line 5 3 2 FRAG fragment description Name Default Units Description X0 0 um X coordinate of the upper left corner of fragment in the device domain um It ca
23. is GE DUM optional and unique one may skip this Gi Clank eleutede directive or give it a number of subdi El mic alectrade rectives to obtain several photogenera E Neate tion wells Alternatively the Basic L B priu directive is mandatory and unique A ny newly created project will contain all juemwe 0000 0 mandatory directives with parameters assigned default values Mandatory Figure 2 2 Project Settings tab directives cannot be deleted Context sensitive menu is visible MICROTEC 4 0 User s M anual 17 M icroT ec User Interface Chapter 2 18 MICROTEC 4 0 User s M anual MICROTEC GRAPHICS SIBGRAF MICROTEC 4 0 User s M anua 19 Chapter 3 M icroT ec Graphics SibGraf 3 1 Introduction SibGraf is a fast and user friendly software tool for plotting l V curves and two dimensional dis tributions of the electrostatic potential carrier and current densities Fermi quasi potentials gen eration rate and electric field components as well as several other functions It is menu driven and includes on line help SibGraf generates 3D plots contour lines color maps 2D cross sections of 3D plots and 2D plots for l V data 3 2 SibGraf 2D Output This function allows you to plot any column a product DM E per ewm En EUM of any two columns or a ratio of any two columns as a ee e e es 0 function of any column in the 2D datafile The 2D data file is generated by
24. n EN 2 0 none parameter tao TAUP 1 0107 S Lifetime for holes Neen p NSRP 5 01016 cm Concentration parameter sRH p APSR 1 0 none parameter Bsgy p BPSR 1 0 none parameter CsRH p CPSR 0 0 none parameter OSRH p EP 2 0 none parameter AUGE Auger recombination parameters 2 R G Auger np Nie C Aug nn C Aug pP Symbol Name Default Units Description Chie an AUGN 2 810 cm s Auger recombination coefficient Cray AUGP 9 9 1032 cms Auger recombination coefficient SURF Surface recombination parameters 2 NP Nie R G o R7 G surr N Nig Vsp D Dig Vn Symbol Name D efault Units Description Ven VSRN 11010 cm s ee recombination velocity for elec rons MICROTEC 4 0 User s M anual 93 Device Simulation Symbol Name Default Units Description Vsp VSRP 11010 cm s Surface recombination velocity for elec trons RADI Radiative recombination parameters R G a4 B np ni Symbol Name Default Units Description B RATE 11014 cm3 s Radiative recombination coefficient 6 6 19 AM P Impact onization This directive contains two unique subdirectives IONE and IONP IONE Impact ionization exponent D n A CET For four ranges of electric field 0 Eo Eg E Ex E gt E am ap Py by are defined below b Gav
25. property of the matrix equation to be solved symmetrical 5 diagonal matrix with diagonal dominance For each mesh node the difference mass balance equation is written For nodes adjacent to an oxide boundary the segregation flux of an impurity caused by oxide motion is included 2 The total impurity dose within the semiconductor and oxide is conserved to the extent of the floating point accuracy of the computer For the solution of several coupled diffusion equations the finite difference equations of each impurity are solved sequentially with initial values of impurity concentrations taken from the previous iteration or previous time step Iterations continue until the solution for all impurities converges to a given accuracy The incomplete factorization method 13 combined with the conjugate gradient method 14 are employed to solve the equations of the 5 diagonal matrix The algorithm was tested by comparing results with examples published in papers 3 5 6 10 The following example of LOCOS process simulation demonstrates CPU time requirements 2 The boron is implanted with 100 K eV energy and a 1014 ions cm dose and the arsenic is implanted with 100 K eV and a 10 ions cm dose A n annealing step at 1000 C in a wet ambient follows for 30 minutes Ten minutes of CPU time were required for this example using a mesh of 45x45 nodes on a 25 MHz PC 386 The same CPU time on a 12 MHz PC AT 286 was required for the simulation with a mesh of
26. redraw itself automatically once a window covering itis moved Redraw Redraw current plot Zoom Out Turn off zoom can also be done with ESC key Annotate See section 3 5 Annotate Help Index Open a window with the help index About Displays SibGraf info M ap Set Contours The Set Contours subitem under the View menu item of the SibGraf M ap window opens a window where the user can assign the levels at which the contour lines are drawn for the current surface A contour map is shown in figure 3 9 Automatic The user can assign the start and the step values for Z or Log Z and choose whether all or none of the contour labels are shown M anual The user can add a new contour line by pressing the Add button and specifying Z or Log Z values for it remove an existing contour line by choosing it in the table and pressing the 26 MICROTEC 4 0 User s M anual Chapter 3 M icroT ec Graphics SibGraf Jm Remove button or modify the existing contour lines by c changing their Z or Log Z values The check box in La EEE aca LE Ju front of each level value indicates whether or not the con tour labels for all contours at this level are shown Ee Br view fee i Tafi zl wis bee The user can also modify an existing contour line and its label by positioning the mouse on a particular label on the plot and pressing the right mouse button A menu will appear through which the u
27. select Add Parameter alist of available parameters pops up Select an item and click OK If you click on Add Subdirective or Insert Directive a list of available directives or subdirec tives pops up Select an item and click OK A brief description of the directives subdirectives and parameters is given in the selection windows A more detailed description may be found in later chapters where each simulator is described in detail The most convenient way of starting a new project is to go to the Select Project window select an existing project similar to the desired one and then click the Copy button A new project will be created with copy appended to the old project name Edit the name in the Name window and click the Update button To modify directives parameters switch to the Project Settings page as described above If you need to start a new project type the name of the project in the Name window select a method in the Method window and click the Add button A project with default directive parameter settings will be created Change the current page to Project Settings and edit the parameters as described above To run a simulation click the Run button A fter the simulation is complete you may display the results by clicking on the 2D Output or 3D Output buttons for plotting l V curves or 3D colour map plots of two dimensional distribut
28. term x in the drift components of 4 5 is due to the band gap narrowing effects and MICROTEC 4 0 User s M anual 65 Device Simulation Chapter 6 is treated accordingly to the Slotboom model 6 1 pta qd e Zi 65 where V Np t N Temperature dependence of the bandgap is as follows E T I gu 7 ET EQ TES 6 7 Intrinsic carrier concentration is E hj T NcNzexo 5 6 8 Effective density of states 3 2 NeT N 300 zpg 6 9 3 2 NAT My300 5 7 6 10 6 2 2 SRH and Auger Recombination and Impact onization The Shockley R ead H all recombination A uger recombination and avalanche generation are taken into account R G R G sgy H R G guger Gay 6 11 2 Np Nie 6 12 MENGI TO t P Nie Tp R G sgy 66 MICROTEC 4 0 User s M anual Chapter 6 Device Simulation R G auger AP Con Cop 6 13 using concentration dependent lifetimes AI 6 14 and an analogous expression for holes Impact ionization is modeled using the Chynoweth model 7 Gay Ap j t el pl 6 15 where a a exp ead bol d ETO and a apex TETO 6 2 3 Surface R ecombination Surface recombination takes place at the interfaces semiconductor oxide or at the surface of non ideal for example polysilicon or Schottky contacts The recombination rate is described by the formula 2 np Nie x 6 17 N Nig Vsp D jg Ven R
29. 06 107 cm s Hole saturation velocity Vp UNP 2 2 none Exponent of normalized temperature in the numerator for holes MICROTEC 4 0 User s M anual 91 Device Simulation Chapter 6 Symbol Name Default Units Description Es XIP 3 7 none Exponent of normalized temperature in the denominator for holes 0 ALPP 0 7 none Exponent of impurity concentration for holes Coto GSRP 1 0 none Low field reduction factor for hole mobility Bo BETP 1 0 none Exponent used in the field dependent hole mobility for parallel electric field 6 6 18 REC Recombination parameters This directive contains four unique subdirectives SRH AUGE SURF and RADI SRH Shockley R ead H all recombination parameters 2 R G Er rr O ir SRH nnyexp Eg KT t P Nig XP E q KT Tp t Tho n D N N OsgH n Cee Bsan Cae J Csgy As a T P ee eet ee p N N OsRH p Uso t Bm go Conn op Symbol Name Default Units Description ES ETRA 0 0 eV Energy level of SRH trap relatively to the intrinsic Fermi level Tao TAUN 1 0107 S Lifetime for electrons NSRH n NSRN 5 01016 cm Concentration parameter Asru n ANSR 1 0 none parameter 92 MICROTEC 4 0 User s M anual Chapter 6 Device Simulation Symbol Name Default Units Description Bsr n BNSR 1 0 none parameter CSRH n CNSR 0 0 none parameter OSRH
30. 07 cm s Saturation velocity BIPO Bipolar mobility model 90 1 E i n 300 Ms nN Ep Gurt n d Sn 500 Vn N min n N ref 2 1 1 Eco y MICROTEC 4 0 User s M anual Chapter 6 Device Simulation MN Ep E ng N Ep 1 1 d B V satn Symbol N ame Default Units Description Un min UMNM 55 2 cm v s Minimum electron mobility Hn max UMNX 1430 cm v s Maximum electron mobility Mera CREN 1 07 1017 cm Reference impurity concentration for elec trons ES ECNM 6 49 104 V cm Critical electric field in the perpendicular electric field mobility for electrons Vatn VSTN 1 07 107 cm s Electron saturation velocity V UNN 2 3 none Exponent of normalized temperature in the numerator for electrons Es XIN 3 8 none Exponent of normalized temperature in the denominator for electrons a ALPN 0 733 none Exponent of impurity concentration for electrons Cae GSRN 1 0 none Low field reduction factor for electron mobility p BETN 2 0 none Exponent used in the field dependent elec tron mobility for parallel electric field T UM PM 49 7 cm v s Minimum hole mobility TAIYA UM PX 479 cm v s Maximum hole mobility Net p CRFP 1 6107 cm Reference impurity concentration for holes E np ECPM 1 87104 V cm Critical electric field in the perpendicular electric field mobility for holes VAA VSTP 1
31. 2 Project Settings Page tacks oos to teneo pete cbe doe eda 16 3 MicroTec Graphics SibGraf usara nl seat 19 3 Introduction e O eo a ea a o ER AO 21 32 SibGraf 2D OUMU ssa II E dat YS ae alor LA ded ae ES 21 PU Bee tate eek e Betas atl a S sse E E esa M es 21 PA A N EN whee lt ryt Gee 22 A AAA TIA RUWA TIE MAUA ew AG MAU oad Aste OAC 23 YA AA LO Ka sired oe he n poe a oA bt bod met od 23 Help III AAA De 23 Zi AA AA AA AA ta E aloe dehet 24 ZANT OO MH al sa Sunt cin WAA od ny hg A nh ot AO 24 2D Data Ple TUCU Sane o ebd eser re Rh ee a Gran 24 3 3 SibGrar M ap Edit Me ss vs bos ev br De 25 AA TEL TD II RY 25 Pape Sect lakh a Poor but e eret evita bL Ete pup tius 25 PAIS AS AA SN ete AEG eNO ENE Sy RNG ca sy NEG 26 AMO EC 26 Helps dte ARAN 26 Maps See ContODES rosarina ae Rer a CMT 26 Map Status Bal Ot chad one kat a a ea oe eo vll ea a esu den p pd 27 Map Tool Baley suce se art EO der cre RE EEN hu XU e v Ohad EA ted ab ka 27 34 SibGraf 3D Outputs e ul nes Y lA ah te ee d BY aoe 28 i esr Si tte CLE E a ON TM 28 POE sens ole ese harsh A he t P ee D bass 28 A ii bw oett a EE RG do dba ow AER ieee d 29 Annotate eC ERE TOT I DT eae ale Ds A a S 29 Help 253 wore ee roe ee wor re a wer nore a eer rome ee reer ere 29 3D Stats Bal we rcr NRO 29 3D T eol Bases niei by SS te otn o ut LEAN t e t M hs 29 AMO oder node e ble oen e iol V ob Ee bold Ro OL See A 30 sorde wer 30 Bd Directives id Mao a OE LG Rc td i wae ra wks 30 A PROCES
32. 52 and for ej ej the relation e 841 40441 t Ci jt d i 6 53 i j 72 MICROTEC 4 0 User s M anual Chapter 6 Device Simulation is valid The conventional Gummel decoupled scheme converges slowly in the case of high injection level To improve the convergence a modified linearization of the discretized Poisson equation 3 has been introduced described in the following section Initial guess strategy which is particularly important for the code efficiency and stability is also described below 6 3 7 M odified linearization of the discretized Poisson equation The discretized Poisson equation is k k k AY i Ani j POY Di j Np NA j 6 54 The superscript k is the iteration number The dependencies of A and AA upon y are shown explicitly in equation 6 54 to emphasize the nonlinear nature of the Poisson equation Failure to correctly take into account this non linearity leads to divergence when sequentially solving the Poisson and continuity equations Gummel 14 used an exponential dependence n exp y Ph P exp 9y w to linearize equation 6 54 The quasi Fermi potentials P and p were considered fixed when iterating over the non linear equation 6 54 and 9 were updated only when solving the continuity equation This is a good approximation when one has a rather accurate initial guess for q However when high injection occurs the Gummel iterations converge slowly W e propose u
33. 6 6 11 DOP Analytical doping data This directive may include any number of DOPA subdirectives The analytical doping profiles are described by a superposition of wells For each well is defined by one DOPA subdirective according to the following formula N well No exp foo LX Kx x J ree Garvan Gran L L L x y y The concentration in every well is a constant equal to M in the rectangle X left Y top X right Y bottom and decreases as a Gaussian beyond the rectangle M is the maximum concentration in the well itis positive for donors and negative for acceptors DOPA Doping well Name Default Units Description DOP 1 1018 cm3 M aximum concentration in the doping well XLFT 0 um Left edge of the doping well XRGT 1 um Right edge of the doping well YTOP 0 um Top of the doping well Y BOT 1 um Bottom of the doping well ALX 0 05 um Characteristic length in X direction MICROTEC 4 0 User s M anual 81 Device Simulation Chapter 6 Name Default Units Description ALY 0 07 um Characteristic length in Y direction DOPN Numerical doping data The only parameter in this directive is the doping data file name In this case the doping data file should contain doping data generated by SiDif or post processed by M ergl C which in turn uses output files generated by the process simulator SiDif Name Default Units Descript
34. Micro Tec Software Packagefor Two Dimensional Process and Device Simulation Version 4 0 for Windows User s M anual Siborg Systems Inc Copyright 1994 95 96 97 98 by Siborg Systems Inc All Rights Reserved First Printing January 1998 Photocopying or any other reproduction of any part of this document violates copyright law Additional copies of this document are available from the publisher Siborg Systems Inc 24 Combermere Cres Waterloo Ontario N2L 5B1 CANADA Phone 519 888 9906 FAX 519 725 9522 E mail microtec siborg ca Web http Ww w siborg ca Trademarks MicroTec Sipif Y M ergl CT SemSim and SibGraf are trademarks of Siborg Systems Inc M icrosoft M S DOS are registered trademarks of M icrosoft Corporation IBM isa registered trademark of International Business M achines Corporation Chapter Table of Contents 1 Gaming Stated idad eds 7 A POI A A grate ge asa aa 9 1 1 1 MicroTec The Semiconductor TCAD Calculator 9 1 1 2 Technical AP ANCES AAA we bad a edad m cede ely SE eet edes 10 T2 nStaltimg MUCEO T Cac bs am task nee eto aba are ect ue Sess Rw Wa 10 1 3 OUI SUIT Eos ote tb Ep bebe thoes E MEE bie tues Mies te EUER 11 2 MicroTecUserliInterface anuanan 13 2 1 MOU 33 a x5 AA AA WA KA d 15 22 RUAN M IEFOLGC ca ide II ER ya 15 2 2 1 Select Project page sx mut Pii ena uate vite Pie a Be ee Tet pesa dta 15 2 2
35. Project shown in figure 2 1 comprises the following Run Bar with Run Edit 2D Output 3D Output Help and Exit buttons Name Text Box showing the current project name Method Text Box showing the simulator used for the current project Project List Window showing the list of available projects Project Description Window with a brief description of the current project Method Description Window with a brief description of the current project simulator Project Handling Bar with Add Update Copy and Delete buttons To select a project in the project list window on the Select Project page click the left mouse button on a project name The corresponding project and simulator name as well as project description will appear in the Name and Method text boxes and Description window respectively If you need to change a project name or project description edit the text in the appropriate win dow and click the Update button If you need to start a new project type a project name in the Name window select a method in the M ethod text box and click the Add button A project with default settings will be created Change the current page to the Project Settings page and edit the parameters as described in the Section Project Settings Page on page 16 When you start a new project you will need to select the appropriate M ethod in t
36. S SIMULAUON o qas aree a ON Lr b EP p E ed ar ra Va ED A OE 33 Z b ro A o reat edocet od EE depo E Rad 35 MICROTEC 4 0 User s M anual 42 Physical Model A e Nase POL ER ERST HC etc nar rea esa neca eB Can on 4 2 1 Diffusion coefficient 4 2 2 Oxidation enhanced diffusion 4 2 3 Analytical okidationmodel A 2A OA NIA d Dex ducta AI oes 42 5 LON Implantatie ea AI AI d tee Coo 4 3 Sim lation algorithm ctl o o es uot T4 Vaters eot OL C se 4A References in daro mte Pes pa Oeste EE Oe MANA dci dod rms Ay Rund SIDIN pine nth aci gine Pe de re d e Y CR E adc tonat ndis ASI IAE da oc Tora e ex Abe xe ph be kim m wie de dew dt 4 6 1 SiDif Directive scu EM 4T SiDif Dasic UIC CS dorar Sine Seta gine ta was MESH computational domain and mesh parameters SUBS substrate Parametros SOLV numerical solution control o us ia rta xot n Ees pad Qa PT d PH DE phosphorus deposition drid Y iR e BODE boron deposIllofi s cia x te c c co X e xao V eor a ASDE arsenic depo TOU ceno Da irri eno D Wa coin doce se Qr n t PHIM AA ule ee PA ERR TP ik 2 pet EE ERN BOIM boron implant sre wilt oet XE na o ccm ER t Te bee ASTM arsenre UTIlanb yates O Moe Bt vta BY Rs OXID oxidation parameters a eGo A ee Vs oe e ANNE annealing parameters 2 cic ou eese lob ied ow eR rey ren EPIT epi layerformati N eres eceran Ue Ev e
37. SemSim and represents IV data and transconductance data W hen you click on the 2D Output button in the main M icroTec window a new window pops up with five menu choices File Plot View Annotate and Help The subtopics avail able under these menus are described below To zoom in on a portion of the graph use the left mouse button as described in the section titled Zooming below Y ou may also use the Annotate command which is also described below The Tool Bar buttons allow you to x nn v arise change the current point and curve switch to and from logarithmic scale and delete the current curve shown Figure3 l SibGraf 2D window in yellow M ore information is available in the Section 2D Tool Bar on page 24 File Open Open a picture file mtp previously created by this program Load Load data from a file containing 2D data e g IV curves 2d See 2D Data File Struc ture on page 24 Save Save the plot to the picture file mtp that is currently open If there is no picture file that is currently open if the Load function was used instead then this function will behave as the Save As function described below SaveAs Save the plot to a picture file mtp A window will be provided to allow you to choose the file name Clear Clear the plot window delete all curves in the window Print Print the plotto a printer or to a PostScript file MICROTEC 4 0 User s M anual 21 M
38. Symbol Name Default Units Description No CINT 3 8731016 cm3 Pre exponential constant for intrinsic concentration E EINT 1 5 none Temperature exponent for intrinsic concentration Ec EGAP 0 60474 eV Bandgap width for intrinsic concentration DIFF Diffusivity of Arsenic Boron and Phosphorus b neo GEA Dp Dye 0 2003 02 0033 Symbol Name Default Units Description Do DX0A 22 9 cm2 s The pre exponential constant for A rsenic Ev DXEA 4 1 eV The activation energy for Arsenic By BETA 100 none The charged vacancy effectiveness for Arsenic Do DX 0B 0 555 cm2 s The pre exponential constant for Boron Fey DXEB 3 42 eV The activation energy for Boron By BETB 3 0 none The charged vacancy effectiveness for Boron Do DX OP 3 85 cm2 s The pre exponential constant for Phosphorous Es DXEP 3 66 eV The activation energy for Phosphorous 48 MICROTEC 4 0 User s M anual Chapter 4 Process Simulation Symbol Name Default Units Description Di DMP 4 4 cm2 s The pre exponential constant for Phosphorous Es DMEP 4 0 eV The activation energy for Phosphorous D DMMP 44 2 cm2 s The pre exponential constant for Phosphorous E DMMEP 4 37 eV The activation energy for Phosphorous OED Oxidation enhanced diffusion D D AD SUY exp d exp Wool Symbol Name Default Un
39. The Log Z button is used to switch to and from a logarithmic scale of the Z coordinate The next button opens a SibGraf 3D window displaying the current function The next two buttons are used to plot the currently selected X and Y cross sections in a separate SibGraf 2D window All subsequent cross section plots are added to the same SibGraf 2D win dow The last button is the Probe button It is used to switch the probe mode on and off see M ap Status Bar above MICROTEC 4 0 User s M anual 27 M icroT ec Graphics SibGraf Chapter 3 3 4 SibGraf 3D Output The user has five menu choices File Plot View Annotate and Help The subtopics available under these menus are described below File Open Open a picture file previously created and saved by this program mts fie Pol re rectos Help e e e 29 ie es o Load Load data from a file containing 2D distribution data 3d Save Save the plot to the picture file that is currently open mts If there is no picture file that is currently open if the Load function was used instead then this function will behave as the Save As function described below Save As Save the plot to a picture file A window will be provided to allow you to choose the picture file name Y o Clear Erase the plot that is currently in the plot win dow Figure 3 10 SibGraf 3D window Print Print the plot th
40. ak 54 DEL4 2 le 4 um The fifth coefficient in Delta for bird s beak 55 DEL5 0 03 um The sixth coefficient in Delta for bird s beak Yo GAMO 0 83 um The first coefficient in Gamma for bird s beak Y GAM1 45e4 um The second coefficient in Gamma for bird s beak Y GAM2 0 039 um The third coefficient in Gamma for bird s beak 13 GAM3 0 76 um The forth coefficient in Gamma for bird s beak Ya GAM4 3 5e4 um The fifth coefficient in Gamma for bird s beak Ys GAM5 0 03 um The sixth coefficient in Gamma for bird s beak MICROTEC 4 0 User s M anual 51 Process Simulation SEGR Segregation parameters Chapter 4 Symbol Name Default Units Description Aseg SEGA 1 0102 none The Segregation coefficient for Arsenic A5 SEGP 1 01022 none The Segregation coefficient for Phosphorous Aag SGBD 13 4 none The Segregation coefficient for Boron in dry O gt Es SBDE 0 33 eV The Segregation activation energy in dry O5 Aseg SBWO 65 2 none The Segregation coefficient for Boron in wet O gt for orientation 100 Aseg SBW1 104 none The Segregation coefficient for Boron in wet O for orientation 111 e SBWE 0 66 eV The Segregation activation energy in wet O gt A ALAM 125104 um s Pre factor in critical oxidation rate in segregation for Boron Ex ELAM 2 0 eV A ctivation energy in critical oxidation rate in seg regation for Boron 4 9 Examples
41. arsenic the segregation coefficient is large about 100 and usually close to the equilibrium value 11 so that the impurity may be considered to be completely pushed into the silicon In this case Jox CpVox 4 3 At high oxidation rates the segregation may cause concentrations at both sides of the interface to not reach equilibrium values In this case a correction was proposed 10 E WA uS J ox E one me Vos 4 4 where X is the kinetic constant of the segregation reaction Equilibrium values of m were taken from 9 4 2 5 lon implantation lon implantation is widely used now as a standard tool for the doping of semiconductor wafers In SiDif an analytic ion implantation model is employed In a one dimensional case the implant is described by a Gaussian distribution 1 y Ry Ky e 4 1 N2TO 26 where Rp and o are the projected range and vertical standard deviation respectively and y isthe MICROTEC 4 0 User s M anual 39 Process Simulation Chapter 4 distance from the top of the wafer material The two dimensional implant profile is described by the formula 15 vnl de i where x and x are the coordinates of the left and the right edges of the grid cell To obtain the final implant distribution expression 4 2 is integrated over the exposed surface of the wafer 4 3 Simulation algorithm The finite difference technique 2 was chosen for the diffusion equation discretization due to a
42. at is currently in the plot window to a printer or to a PostScript file Export Data Allows you to transfer data from the graph into an ASCII file See previous sec tion for the file format The file can then be imported using the Import Data command Import Data Allows you to add new data from a file to the graph The file may contain a few curves For every curve the first line for every subset of data includes the number of points in the curve and name of the curve followed by two columns of data for X and Y axis respectively New Window Opens new Sibgraf 3D window Exit Closethe SibGraf 3D window Plot Source Opens a window which shows the data source for the current surface Fields cannot be edited Select gives you a variable list figure 3 8 from which you can chose an item to plot on the graph see figure 3 8 If the current plot was invoked through the Open function Source is the only subitem under Surface If the file with 2D distribution data was loaded through the L oad function all the vari ables that may be displayed are contained in the file and are listed in the Select window 28 MICROTEC 4 0 User s M anual Chapter 3 M icroT ec Graphics SibGraf View Options Opens a window where the user can assign labels for horizontal and vertical axes and the title for the plot The user can also specify the lowest value of the logarithm function corre sponding to an argument approaching zero
43. column allow the user to choose which column willbe 7 7 Pese the X axis and which will be the Y axis The third s Chos Bee check box allows the user to choose a column which will be multiplied by the column chosen as the Y axis Figure 3 2 Plot A dd menu In this case a product of the respective elements of the two columns will be plotted The fourth check box allows the user to choose a column which will be used as a divider for the Y axis In this case a ratio of the respective elements of the two columns will be plot ted The setup necessary to plot current gain B Ic Ig is Oi Farb B al3 pr Mata lor pu Care Hama ja n THB MARIN shown in figure 3 2 x s n The user can type the name of the curve being created aa fe into the Curve Name box The default curve name is Ea the name of the column chosen as the Y axis W hen all M a Chine required information is selected at least the X and Y axes must be given the curve may be added to the plot by pressing the Add button Once all the desired curves have ben added click Close to return to the SibGraf 2D window The data used to create a curve may be viewed later by selecting the Curve Source menu which brings up the window shown in figure 3 3 Figure 3 3 The Curve Source window 22 MICROTEC 4 0 User s M anual Chapter 3 M icroT ec Graphics SibGraf Copy Copy the
44. current curve from the plot to the SibGraf clipboard This feature combined with Paste is used to create compillations of curves Paste Add the curve from the SibGraf clipboard to the current plot Delete Delete the current yellow curve from the plot Source Open a window which shows the data source for the current curve The curve name may be changed from this window Line Color M arker Allows changes to the corresponding attributes of the current curve View x Axis Limits Allows setting the minimum and maximum values for x and y see figure 3 4 Also allows selection of xme po E the vertical offset option The vertical offset creates a Amos panama vues puni Pace between the curve and the axis lines AN A E Options Opens a window where the user can assign MMM labels for horizontal and vertical axes and the title for the Figure 3 4 Axis Limits window plot see figure 3 5 The user can also specify the lowest value of the logarithm function corresponding to an argu NEI ENS ment approaching zero The Show Markers and Show w Kleber p m E zs Fe Lines check boxes apply to all the curves in the window ame Information in this window may be saved by pressing the Log consta Save button A file setup mt will be created and the ds em A Lure Marium settings will be read every time a new SibGraf 2D window ve NS See is opened e tae tw Grid Legend Switch grid and
45. dow change your current directory to CM T 305 and extract M icroTec compo nents using the command pkunzip mt305 zip 4 Register you computer using install command at the command prompt you will need the serial number from file serial n txt on the floppy or request one from microtec siborg ca install 0 File inst pas will be created Please zip this file and E mail the zipped archive to microtec siborg ca as an attachment by E mail We will then register your computer and send you another inst pas file Please include the name of the contact person phone and F ax numbers to facilitate communi cation should it be required K eep a copy of the inst pas at all times 5 Unzip received inst pas in the M T 305 directory and run install i This will complete the installation procedure You may run M icroTec without registering it In this case it will run in a demonstration mode where you can run any process simulation in a fixed domain 0 7 by 0 7 microns Y ou will also be able to simulate an NM OSFET with 1 um Leff and Tox of 0 02 um You cannot 10 MICROTEC 4 0 User s M anual Chapter 1 Getting Started change the transistor structure e g location of electrodes doping distribution and the domain size but you can change the voltages number of nodes model parameters etc Without registration for all other device simulation examples included in the distribution package you can only plot the output results and edit t
46. ducational purposes due to its completeness and ease of use It enables development of a set of problems for a tutorial in semiconductor device physics with minimal effort The goal of such a computer aided course would be to teach students basic ideas about modern semiconductor device design A flexible and easy to use graphic interface allows the user to output results of the process device simulation on essentially any printer or plotter or into a file Despite its apparent simplicity M icroTec covers all the basic needs of semiconductor process device design complemented with efficient and flexible graphics tools It is much easier to use than any other tool of its kind M icroTec is a must for those who want to understand physics of semiconductor devices without knowing much about computers or numerical methods and who do not have much time for learning new process device simulation tools M icroTec is an excellent tool for managers R amp D engineers students professors and researchers and can be referred to as aTCAD calculator M icroTec is based on the diffusion drift model and the present version does not include energy balance It employs the finite difference technique on a rectangular auto adjusting mesh Only steady state analysis is available in the present version of M icroTec Physical models mobility life time recombination and impact ionization implemented in M icroTec are essentially the same as those used in the widely used co
47. e is the only subitem under Surface If the file with Contigit hole pesidual 2D distribution data was loaded through the Load function ey HEN all surfaces contained in that file are listed after the tem Source Any of these surfaces may be plotted Figure 3 8 Plot Surface menu MICROTEC 4 0 User s M anual 25 M icroT ec Graphics SibGraf Chapter 3 View Axis Limits Allows you to set minimum and maximum values for the x and y vertical and hor izontal axis See figure 3 4 The vertical offset option is not available Options See Options in the Section View on page 23 Set Contours See the Section M ap Set Contours on page 26 Directives Allows you to make the directives for the SibGraf M ap Edit windown visible You can change the directives in the edit window but not in the map window If you are in the SibG raf M ap window you may change the directives in the Projest Settings tab of the main menu For more information see Section Directives on page 30 Rainbow8 Rainbow16 BlackW hite Contours Each of these four items describes one of the possible four SibG raf M ap representations M ap using 8 colors M ap using 16 colors M ap using 8 levels of gray and Contour M ap Grid Legend Show hide discretization mesh and legend for Color M ap Tool bar Status bar AutoRedraw Shows or hides the tool bar and status bar Turns auto redraw on or off With autoredraw on the window will
48. e Default Units Description EPSD 3 9 none Therelative dielectric permittivity of the oxide EPSS 11 8 none The relative dielectric permittivity of the semiconductor 86 MICROTEC 4 0 User s M anual Chapter 6 Device Simulation WORK Semiconductor work function Name Default Units Description FIS 4 17 eV Semiconductor electron affinity 6 6 17 4M OB Mobility models This directive contains four unique subdirectives CONM YAMA LOMB and BIPO CONM Constant mobility model Symbol Name Default Units Description ta UMNO 1000 cm2 V s_ Constant mobility for electrons oo UMPO 500 cm v s Constant mobility for holes YAMA Yamaguchi mobility model u N E Eg p QU Ep 1 mW E e R R EN G me s V r 1 N 2 7 1 ta E4 i C 1 1 2 Symbol Name Default Units Description Hno UMNO 1410 cm2 V s M aximum electron mobility S SN 350 0 none Doping concentration factor for electrons N RSN 3 0 1016 cm Reference doping concentration for electrons MICROTEC 4 0 User s M anual 87 Device Simulation Chapter 6 Symbol Name Default Units Description O ALN 1 54105 cm V Perpendicular electric field factor for electrons Vos VSN 1 036107 cm s Saturation velocity for electrons G GN 8 8 none Parallel el
49. e dopant In this case the surface acts as source with a constant concentration The predeposition occurs in the surface region from 0 to XD if XD is positive or from XD to XX if XD is negative If XD is 0 or omitted there is no predeposition If XD is larger then XX the dopant is deposited throughout the fragment surface ES 1019 Surface concentration of the dopant for the deposition M ay be omitted if XD is omitted COMM Comm none Comment line BODE boron deposition The same parameters are used as in the directive PH DE ASDE arsenic deposition The same parameters are used as in the directive PH DE PHIM phosphorus implant Name Default Units Description XM 1 um Position of the implantation mask edge The dopant is implanted through the window from 0 to XM if XM is posi tive and from ABS XM to XX if XM is negative For uni form implantation all over the domain XM should be much greater then X X M ake it 0 or omit it to suppress the implanta tion DZ 1012 cm Implantation dose ignored if XM 0 EN 40 K eV Implantation energy up to 1000 COMM Comm none Comment line MICROTEC 4 0 User s M anual 45 Process Simulation BOIM boron implant Chapter 4 The same parameters are used as in the directive PHIM ASIM arsenic implant The same parameters are used as in the directive PHIM OXID oxidation
50. e 3 1 SibGraf 2D window s apa va eco e hh ver oe Cea oec EV ne 21 Figure 3 3 The Curve Source WINdOW inet dc ti 22 Figure 3 2 P IobfA dd s SOY aria na 22 Figure 34 Axis Lits WIDOOW cerro doo 23 Figure 3 5 2D Options WINDOWS 3 e ae aa 23 Figure 3 8 Plot Surface Menu 15e a a eb ss 25 Figure 3 7 SibGraf map WINdOW paisas cana ride alada 25 Figure 3 9 CA MUM AAAH 27 Figure 3 10 SibGtaf 3D WINGOW untada lt AWA KAA ha Re X es 28 MICROTEC 2 02 User s M anual 99
51. e of the region Annealing follows at 1100 C for 1 hour in a wet oxidizing ambient to create a LOCOS structure M ESH N X 25 NY 35 X X 2 Y Y 2 1M 21 COMM LOCOS SUBS PH 1E12 B0 1E15 AS 1E12 OR 111 ASIM X M 1 EN 2200 DZ 1E 15 BOIM XM 1 EN 100 DZ 1 E 13 ANNE TC 1100 TM 3600 T A 100 0X 2 X O 1 P O 0 9 4 9 4 Doping by deposition The substrate is initially doped with phosphorus at 1015 cm Then boron is deposited on the whole surface with a surface concentration of 101 cm for 30 minutes at 1000 C After this arsenic is deposited through the mask on the left side of the region with a surface concentration of 102 cm 3 for 30 minutes at 1100 C MICROTEC 4 0 User s M anual 53 Process Simulation Chapter 4 M ESH N X 235 N Y 35 X X 2 Y Y 2 5 1M 1 COM M Deposition example SUBS PH 1E12 B0 1E13 AS 1E12 0R 111 BODE X D 3 CS 1 E18 ANNE TC 1000 T M 1800 T A 2200 OX 0 ASDE X D 1 CS 1E20 ANNE TC 1100 T M 1800 T A 100 OX 0 4 9 5 Buried layer and epitaxy A substrate is doped by boron at 1019 cm arsenic is implanted in the whole region at 300 K eV and 10 ions cm and annealed at 1000 C for 1 hour in an inert ambient Epitaxy follows for 10 minutes at 1200 C resulting in a layer thickness of 2 microns which is doped by arsenic at 10 cm Then boron is implanted at 100 K eV and 101 ions cm into the left side of the region and annealed at 1000 C for 60 minutes A non
52. ectric filed factor for electrons Ven VCN 4 9 106 cm s Phonon velocity fitting parameter loo UMPO 480 0 cm2 V s M aximum hole mobility 5 SP 81 0 none Doping concentration factor for electrons Nip RSP 4 0 1016 cm Reference doping concentration for holes OL ALP 5 35105 cm V Perpendicular electric field factor for holes Vp VSP 1 2107 cm s Saturation velocity for holes G GP 1 6 none Parallel electric filed factor for holes Ves VCP 2 928 109 cm s Phonon velocity fitting parameter LOM B Lombardi surface mobility model 0 Ho Hac Hp Us 7 Ep LEE E T I p CN T Lo y Emax Ho s Ee H masi T Imax 300 i ee a CaP 300 E iste 1 us Ep Es T pp N Ep DO suspe fen Vsatn 88 MICROTEC 4 0 User s M anual Chapter 6 Device Simulation Symbol Name Default Units Description B BN 4 75107 cm s Fitting parameter for perpendicular electric filed E CON 1 410 Fitting parameter for perpendicular electric filed and doping concentration 0 CPON 0 125 none Exponent of the doping concentration parameter Ho UON 52 2 cm v s Minimum hole mobility Umar UMAN 1 42 103 cm2 V s Maximum hole mobility l4 ULN 43 4 cm v s Concentration correction term C CRN 9 681016 cm Critical doping concentration on CSN 343102 cm Critical doping concentration in the correction term P PCN 0 0 cm s Concentration correction of the minimum mobility a ALPN 0 68 none Expone
53. ed in the centre of the plot area To move the existing Annotate Text object first select it by clicking the left mouse button inside the text region Then the text region can be moved to the desired position by dragging it with the left mouse button If the content of the text object is to be changed the user should first select the text object then choose the subitem Edit under Annotate in the main menu The user can delete annotation lines or text by selecting them as the current annotated object as described above and then choosing the subitem Delete under Annotate in the main menu 3 6 Zooming The user may zoom in on a particular rectangle of any 2D 3D or M ap plot Position the cur sor over a point on the plot that you would like to use as the corner of a new plot Press and hold the left mouse button as you move the mouse which will show a rectangle on the plot correspond ing to the area that will be shown on a new plot When you have a rectangle defined that covers the area of the plot that you would like to zoom in on release the mouse button and the plot will be replaced by a plot of the selected area To restore the original plot you may press the ESC key or select Zoom Out from the View menu In SibGraf 2D and M ap windows you may unzoom the plot by selecting a rectangle outside the plotting area using the left mouse button 3 7 Directives In both the SibGraf M ap and SibGraf Edit windows under the View item in the main menu
54. eft edge of the oxide well XOXR 1 um Right edge of the oxide well YOXT 0 um Top of the oxide well YOXB 1 um Bottom of the oxide well QOXL 0 cm Qss at the left edge of the oxide well 96 MICROTEC 4 0 User s M anual Chapter 6 Device Simulation Name Default Units Description QOXR 0 cm Qss at the right edge of the oxide well QOXT 0 cm Qss at the top of the oxide well QOXB 0 cm Qss at the bottom of the oxide well 6 6 22 REM Remesh region This directive may include up to 20 REM E subdirectives Each rectangular region is defined by one REM E subdirective with the following parameters REM E Remesh region Name Default Units Description COMM Name none Region name NXRM 5 no units Number of extra X nodes in the region NYRM 5 no units Number of extra Y nodes in the region XRML 0 um Left edge of the remesh well XRMR 1 um Right edge of the remesh well YRMT 0 um Top of the remesh well YRMB 1 um Bottom of the remesh well MICROTEC 4 0 User s M anual 97 Device Simulation Chapter 6 98 MICROTEC 4 0 User s M anual Chapter Index MICROTEC 2 02 User s M anual 97 98 MICROTEC 2 02 User s M anual Chapter Chapter List of Figures Figure 2 1 Select Project ID a e at fal Ne 16 Figure 2 2 Project Settings tab ii eset te ace tomatic yate goa ste Dt ERO TA 17 Figur
55. es BAND Bandgap and intrinsic carrier concentration DIFF Diffusivity of Arsenic Boron and Phosphorus OED Oxidation enhanced diffusion DROX Dry oxidation kinetic constants WEOX Wetoxidation kinetic constants LOCO Local oxidation bird s beak formula parameters SEGR Segregation parameters A description of the SiDif directives follows 4 7 SiDif basic directives M ESH computational domain and mesh parameters Name Default Units Description NX 30 none Number of mesh nodes in X direction along the surface It must be greater than 3 NY 30 none Number of mesh nodes in Y direction into the depth of the domain It must be greater than 3 A greater number of mesh nodes gives a higher computational accuracy at the expense of alarger CPU time XX 1 um Domain size in X direction microns The domain should cover a region near edges of all the masks where the two dimensionality takes place YY 1 um Domain size in Y direction microns The domain should be deep enough to cover the maximum expected depth of the implanted or deposited dopant penetration MICROTEC 4 0 User s M anual 43 Process Simulation Chapter 4 Name Default Units Description IM 1 none This key must be 1 for a uniform mesh If it is zero or nega tive the mesh will be exponentially condensed in the origin of coordinates AX 0 none Logarithm of the ratio of two ad
56. for 900 C and lower For an accurate eval uation on a fine mesh the recommended value is 2 10 times lower than the one above Use a smaller TAU if the number of nonlinear iterations exceeds 7 COMM Comm none Comment line EPIT epi layer formation Name Default Units Description TC 1000 uo Temperature of oxidation centigrade TM 2000 S Time of oxidation in seconds TAU 1 S Initial time step in seconds The recommended value is 30 s for a temperature of 1200 C 100 s for 1100 C 200 s for 1000 C and 500 s for 900 C and lower For an accurate eval uation on a fine mesh the recommended value is 2 10 times lower than the one above Use a smaller TAU if the number of nonlinear iterations exceeds 7 PH 1 0102 cm Initial uniform phosphorus concentration BO 1 01012 cm3 The same parameter for boron doping AS 1 01012 cm3 The same parameter for arsenic doping TH 1 um Thickness of the grown epitaxial layer Existing profile of dopants is shifted by TH towards the depth of the domain and the dopant thermal redistribution during epitaxy is evaluated M ake sure that Y Y islarge enough not to lose the buried layer COMM Comm none Comment line MICROTEC 4 0 User s M anual 47 Process Simulation Chapter 4 4 8 SiDif model parameter directives BAND Bandgap and intrinsic carrier concentration n mr oo 8
57. for the linear kinetic coefficient A In the case of wet oxidation P P xand in the case of dry oxidation P a p x The factor OR depends on the silicon orientation 17 If there is an initial oxide film with a thickness of U on the surface of the semiconductor then 4 1 leads to U t 4 4 Bt 4 4 3 Usually only a fragment of the wafer surface is exposed to the oxidizing ambient while the rest of the surface is covered by a nitride mask In this case oxidation in the area near the mask edge is described by the bird s beak formula Ux reds aon ta Uo xm a 44 with the following empirical parameters 10 wa 1 434 85 63 T X U D 4 5 Yo T y4ln Ug 143y 2 3 T Y4x UO 4 6 where xy 1 and 0 for 111 and 100 orientation respectively 4 2 4 Segregation The oxidation of silicon is accompanied by the segregation in other words a jump in the impurity concentration at the moving Si SiO interface The segregation causes an impurity flux density at the interface which may be written as 38 MICROTEC 4 0 User s M anual Chapter 4 Process Simulation J ox ed y m Vox 4 1 where C is the impurity concentration in Si at the SiO boundary m is the segregation coefficient v is the oxide growth rate in the direction normal to the interface and is the ratio of volumes of Si and SiO that is equal to 0 44 For boron m Asegexp 589 A A ex 73 4 2 For phosphorous and
58. he M ethod MICROTEC 4 0 User s M anual 15 M icroT ec User Interface Chapter 2 window The following four options are available SiDif two dimensional SImulation of implantation diffusion and oxidation e Mergl C program for M ERGing fragments simulated by SiDif SemSim two dimensional steady state semiconductor device simulation Batch batch mode simulation of any number of process and or device simulations A nother way of starting a new project is to copy an existing project Select a project and Select Project click the Copy button A new project with copy Raosrtr3 OO O Enhamced NMOSFET ILATY Wih appended to it s name will be NMOSFET 1 pee FUNT INS eee wo created To modify the project NGET Z name change the name in the NMOSFET 4 A Name text box and click the 14 06 AC M Update button in the main ierit a AA n MicroTec window Switch to the Project Settings page and change the parameters as needed MICHOTEC 3 8 20 Ouipus ID Dartput To run a simulation click the Figure 2 1 Select Project tab Run button A fter the simu lation is complete you may display the results by clicking on the 2D Output or 3D Output buttons for plotting IV curves or 3D contour plots of two dimensional distributions of various variables such as electrostatic potential carrier and current densities Fermi quasi potentials elec tric field comp
59. he input data Do not try to run these examples because the doping distribution and geometry of the simulated device will still be that of the NM OSFET 1 3 Quick start Select a project in the project list window on the Select Project tab by clicking the left mouse button on the project name see Figure 2 1 Select Project tab on page 16 The corresponding simulator name will be shown in the M ethod window The simulator name may be SiDif M er gl C SemSim or Batch for the process simulation generation of the device structure device sim ulation or a batch mode simulation respectively In the batch mode you may run several jobs using different tools for example a process simula tion a generation of the final device structure using M ergl C and then a device simulation for the generated device with a number of different IV curves To modify the project settings click on the Project Settings tab see Figure 2 2 Project Settings tab on page 17 Another page of the main M icroTec window will appear showing a directives subdirectives and parameters tree Click on a folder symbol to open it Double click a parameter to edit it If you click on a directive or subdirective with the left and then the right mouse button a context sensitive menu appears allowing Delete Copy Insert Directive or Insert Subdi rective Add Subdirective and Add Parameter If while a subdirective is selected you
60. ice simulation tool SemSim M ergl C merges device fragments simulated by SiDif into a device domain to be used in the device simulation The fragments may be placed arbitrarily in the device domain symmetrized and replicated The output file of M ergl C serves as the numerical doping input file for SemSim M erglC allows one to significantly reduce the fragment size used in the process simulation and hence the CPU time This also significantly simplifies mesh generation for the process simulation 5 2 Running M ergl C To run M erglC from the M icroT ec shell e Select a project corresponding to M erglC or add a new project by selecting M ergl C method in the M ethod window M erglC requires the main input file with the extension INP and one doping data file for every fragment used in the device structure These fragment doping files must be previously generated by SiDif e Edit parameters by switching to Project Settings page of the in the main M icroTec menu Click Run button To run SemSim outside the M icroT ec shell the command line should look as follows mergic project inp Refer to sections below for the description of the input file On the output MerglC generates a doping data file which is used in a device simulation by SemSim If you want to plot the output doping file click 3D Output in the main M icroT ec menu after running M ergl C Note Since the device simulation tool SemSim in the present version of M
61. ion FILE none Name of the file where data previously evaluated using SiDif or M erglC are stored 6 6 12 OXI Oxide This directive may include up to 20 OXID subdirectives Each rectangular region is defined by one OXID subdirective OXID Oxideregion Name Default Units Description COMM Name none Region description PERM 3 8 no units Oxide permittivity XOXL 0 um Left edge of the oxide well XOXR 1 um Right edge of the oxide well YOXT 0 um Top of the oxide well YOXB 1 um Bottom of the oxide well QOXL 0 cm Qss at the left edge of the oxide well QOXR 0 cm Qss at the right edge of the oxide well QOXT 0 cm Qss at the top of the oxide well QOXB 0 cm Qss at the bottom of the oxide well 82 MICROTEC 4 0 User s M anual Chapter 6 Device Simulation 6 6 13 REM Remesh This directive may include up to 20 REME subdirectives Each rectangular region is defined by one REME subdirective REME Remesh region Name Default Units Description COMM Name none Region name NXRM 5 no units Number of extra X nodes in the region NYRM 5 no units Number of extra Y nodes in the region XRML 0 um Left edge of the remesh well XRMR 1 um Right edge of the remesh well YRMT 0 um Top of the remesh well YRMB 1 um Bottom of the remesh well 6 6 14 L E Electrode di
62. ions respectively Click on Plot Add or Plot Select for 2D Output or 3D Output respectively to plot an IV curve or a surface MICROTEC 4 0 User s M anual 11 Getting Started Chapter 1 The 2D distributions available for plotting are electrostatic potential carrier and current densi ties Fermi quasi potentials electric field components etc You may also plot 2D cross sections and IV plots as well as transconductances as a function of applied voltage For more information on the Graphics Tools refer to Chapter 3 12 MICROTEC 4 0 User s M anual MICROTEC USER INTERFACE MICROTEC 4 0 User s M anua 13 Chapter 2 M icroT ec User Interface 2 1 Introduction M icroTec is a shell integrating four programs for silicon process device simulation SiDif two dimensional SImulator for DIFfusion and oxidation e Mergl C program for M ERGing fragments of IC elements SemSim two dimensional steady state SEM iconductor device SIM ulator SibGraf interactive 3D and 2D graphics M icroTec is a highly robust 2D semiconductor process device simulation package which can be run on IBM PCs and compatibles with a reasonable CPU time and low memory requirements 2 2 Running M icroTec The MicroTec main menu has two tabbed windows Select Project and Project Settings that can be viewed by clicking on the named tab Select Project page The first page of the M icroTec main menu called Select
63. irst fragment IF Name of the SiDif output file with the doping data for the fragment It must be separated by 5 4 Examples of M ergl C input file Examples of MerglC input files follow The last three examples differ only in the way the fragments are placed 5 4 1 Viewing a fragment MESH NX 50 NY 245 XX 5 Y Y 23 COMM Fragment view FRAG X 0 0 DX 0 SY 0 OV 11F2MOS OUD 5 4 2 Symmetrical device using one fragment M ESH N X 270 NY 240 XX 22 5 Y Y 1 COMM NM OS Transistor FRAG X 0 1 6 DX 0 7 SY 1 OV 1 IF EXMOS OUD 5 4 3 Vertical BJ T with substrate collector M ESH NX 2150 NY 240 X X 5 Y Y 22 5 COMM Vertical BJT FRAG X024 5 DX 1 SY 0 OV 1 IF BUR OUD FRAG X 0 1 DX 1 SY 1 OV 0IF EMIT OUD MICROTEC 4 0 User s M anual 61 Device formation Chapter 5 5 4 4 Vertical BJ T with a buried layer M ESH N X 2200 NY 240 X X 8 Y Y 23 5 COMM Planar transistor FRAG X 0 4 DX 1 SY 20 OVz1IF BUR OUD FRAG X 0 1 DX 1 SY 1 OV 0 IF EMIT OUD 5 4 5 12L Device M ESH N X 2200 NY 240 XX 210 Y Y 22 5 COMM l2L device FRAG X 0 1 DX 1 SY 1 OV 1 IF BUR OUD FRAG X 0 10 DX 1 SY 1 OV 0 IF EMIT OUD 62 MICROTEC 4 0 User s M anual 6 DEVICE SIMULATION MICROTEC 4 0 User s M anua 63 Chapter 6 Device Simulation 6 1 Introduction A number of software tools are available for two dimensional semiconductor device simulatio
64. its Description AD OEA0 0 0 cm2 s The OED for Arsenic 100 orientation AD OEA1 0 0 cm2 s The OED for Arsenic 111 orientation AD OEBO 1 66 10 cm2 s The OED for Boron 100 orientation AD OEB1 6 11e 6 cm2 s The OED for Boron 111 orientation AD OEPO 14410 cm2 s The OED for Phosphorous 100 orientation AD OEP1 5 65 106 cm2 s The OED for Phosphorous 111 orientation Ex OEE 2 08 eV The activation energy for OED hy OELDY 25 0 um The vertical coordinate exponent for OED hy OELDX 2 0 um The lateral coordinate exponent for OED Bos OEBOX 0 3 none The oxidation rate exponent for OED 4 8 1 Deal Grove oxidation kinetic constants dU B dt BEA Eg B Ep B PB exo 7E 5 OR oy RE Per Por B MICROTEC 4 0 User s M anual 49 Process Simulation Chapter 4 DROX Dry oxidation kinetic constants Symbol Name Default Units Description B BD 0 214 um2 s Parabolic oxidation rate constant in dry O32 Ro BAD 1730 um2 s Linear oxidation rate constant in dry O Eg BDE 1 23 eV Parabolic activation energy in dry O En BADE 2 0 eV Linear oxidation activation energy in dry O gt B BPF 0 75 none Exponent of the effective pressure WEOX Wet oxidation kinetic constants Symbol Name Default Units Description OR ox ORO 0 595 none Orientation coefficient for 100 OR oy OR1 1 0 none Orientation coefficient for 111 r
65. jacent mesh step sizes in the X direction if the mesh is not uniform AY 0 none Analogous parameter for the Y direction Parameters A X AY may be omitted if IM 21 Nonuniform mesh is preferable for a simulation including relatively fine structures near the surface COMM Comm none Comment line SUBS substrate parameters Name Default Units Description PH 1 0107 cm Initial uniform phosphorus concentration BO 1 01032 cm3 The same parameter for boron doping AS 1 01072 cm The same parameter for arsenic doping OR 100 none Lattice orientation COMM Comm none Comment line SOLV numerical solution control Name Default Units Description IB 1 none Batch mode switch If B 1 the default then run without plotting after each processing step batch mode IT 100 none Maximum number of iterations for the linear solver RS 1012 none Residual convergence criterion for the linear solver RL 103 none Relative residual criterion for the linear solver CO 1022 cm 3 Value of the impurity concentration considered to be a back ground COMM Comm none Comment line 44 MICROTEC 4 0 User s M anual Chapter 4 Process Simulation PHDE phosphorus deposition Name Default Units Description XD 1 um Position of the mask edge for a surface deposition of th
66. legend on and off Tool Bar Switch tool bar on and off Figure 3 5 2D Options window Status Bar Switch status bar on and off Zoom Out Turn off zoom can also be done with ESC key Annotate See the Section A nnotate on page 30 Help Index Help index for SibGraf About Display SibGraf info MICROTEC 4 0 User s M anual 23 M icroT ec Graphics SibGraf Chapter 3 2D Status Bar The status bar is the strip at the bottom of the plot window It shows the value of the X and Y coordinates for the current marker on the current curve The current marker is shown in red 2D Tool Bar The tool bar is the line of buttons just below the main B Biot ew dem He menu and above the plot window The first two buttons I 1 1 are used to change the current curve which is shown in tei r5 onn en 09 9 yellow Each click will change the current curve to the next curve The curves are ordered in the sequence they were added pasted The first button cycles upward through the curves and the second cycles downward This can also be done by using the up and down arrow keys on the keyboard The next two buttons change the currently selected point marker on the curve The marker of the current point is red as in figure 3 6 The buttons move the red marker to the left and right respectively This can also be done using the left and right arrow keys on the key board The x and y value of the current ma
67. mmercial simulators MICROTEC 4 0 User s M anual 9 Getting Started Chapter 1 Technical Parameters M icroTec 4 0 is a true 32 bit Windows application and can be run on any PC 386 or higher M icroTec 4 0 uses dynamic memory allocation There is no memory threshold so it can be used even on a computer with only 1 Mbyte memory if the mesh size is not larger than about 2 000 nodes Other commercially available tools typically require about 20 M byte memory for a mesh size limited to 3 500 nodes MicroTec 4 0 device simulation tools require about 8 M bytes of memory for a 20 000 node mesh Typical CPU time for one IV point is less than 1 minute on a PC 486 when using 1 000 nodes For the process simulation tool about 4 M bytes of memory is required for a 20 000 node mesh Simulation of a typical technological route requires 1 10 minute CPU time on aPC 486 The most remarkable features of MicroTec are dramatically reduced memory requirements absolute numerical stability almost arbitrary changes of contact voltages even with impact on ization high speed and very easy to use Graphical U ser Interface 1 2 Installing M icroTec Read about the latest changes in the Installation procedure in the readme txt file on the installation Disk You will need about 4 M egabytes of disk space to install M icroTec 4 0 1 Create directory C M T 305 on a hard disk 2 Copy all M icroTec files from the floppy into this directory 3 Open DOS win
68. n Conventionally they use Newton like methods and this results in numerical instability and relatively high memory requirements Recently new methods for the linearization of the semiconductor equations were proposed 3 4 5 permitting the efficient solution of the nonlinear semiconductor equations The methods use the decoupled or Gummel like scheme 14 significantly reducing the memory requirements Surprisingly these methods appear to be more efficient than the Newton method in a number of instances and certainly are numerically more stable than the latter SemSim as well as its predecessors SIMOS 1 and BiSim 2 is based on the Gummel like decoupled technique and require only 4 Kbyte of memory for a 10 000 node mesh A finite difference technique on a rectangular grid is employed For discretization of the continuity equations the conventional Scharfetter Gummel approximation 11 is used Conjugate gradient methods with preconditioning 12 13 are used for solving the linear systems 6 2 Basic System of Equations The basic equations comprise of the Poisson equation standard notation is used and the continuity equations for electrons and holes V y E n p Np Nj 6 1 0 ly R G 6 2 q n lvj R G 6 3 q p where J pare related to the carrier densities and the electrostatic potential Jn qnu V y x qD Vn 6 4 Jp QPL VOW X qD Np 6 5 6 2 1 Bandgap narrowing The additional
69. n in 3 choosing an exponential dependence we arrive at the generalized Gummel linearization GGL while assuming the densities to be independent of w we arrive at the generalized M ock scheme GM S 16 GGL coincides with the conventional Gummel linearization if the difference of the quasi F ermi potentials at the adjacent mesh nodes vanishes Introduction of the coefficients a a May speed up the convergence of Gummel iterations by up to 7 times in the case of high injection 3 6 3 8 Initial guess strategy The total current continuity equation is used for the evaluation of the initial guess and it is essentially a combination of Eqs 5 6 74 MICROTEC 4 0 User s M anual Chapter 6 Device Simulation VJ y 0 The operator form of the discretized equation 21 is k k Asc ynk Aj pk 20 where An we Ay and A are respectively the finite difference operators of the continuity and Poisson equations The superscript k is the iteration number and v is the electrostatic potential from the previous bias Linearization of 22 with respect to sy y ys and the assumption that the carrier concentrations n and p remain unchanged give k 1 k 1 k 1 k k k AQ um up 98y Ayna AL yr Op where A w n p is the derivative of A y nk A Cy pk with respect to y A ya r X Ay n p 8y j 8 DVi jt Dj Bw j 4 DV jt C AWi41 d Vi j To simplify the formulae and to reduce the number of indexes i
70. n exceed the overall length of the device if you want to invert the fragment over the vertical symmetry axis SY none Type of the fragment symmetrization If SY 0 there is no fragment symmetrization SY 1 means symmetrization over its right edge that is the fragment is extended symmetrically to the right and SY 1 means symmetrization over the left edge or extension to the left DX um Length of the fragment extension or a piece fitted between the symmetrical regions It must be larger than 0 It is ignored if SY 0 This region is filled with the doping profile from the fragment borders which face each other 60 MICROTEC 4 0 User s M anual Chapter 5 Device formation Name Default Units Description OV 1 none Extension of the doping profile of the fragment to the whole device domain It is needed to create the basic structure for example the initial doping implantation to the whole device domain or buried layer If OV 1 the doping values on the bot tom edge of the fragment are continued to the bottom of the device domain and then the profiles on the right and left edges of the fitted fragment are extended uniformly to the right and left borders of the device domain respectively If OV 0 the fragment is placed over the region replacing the doping which was there before No extension to the right left or down is made in this case OV 1 option is preferable for the f
71. nt in the concentration factor p BETN 2 0 none Exponent in the concentration correction factor y GAMN 2 5 none Temperature factor exponent DELN 5 821014 V s Acoustic term parameter Beorn BESN 2 0 none Exponent in the saturation velocity Visi VSAN 107107 cm s Saturation velocity Analogous parameters for holes note that expression for u in this case is different HCN T ugexp P N Emn E S e n MICROTEC 4 0 User s M anual 89 Device Simulation Chapter 6 Symbol Name Default Units Description B BP 9 93107 cm s Fitting parameter for perpendicular electric filed Cc COP 8 84 10 Fitting parameter for perpendicular electric filed and doping concentration 0 CPOP 31710 none Exponent of the doping concentration parameter Ho U OP 44 9 cm v s Minimum electron mobility Umar UMAP 470 cm v s Maximum electron mobility Hy ULP 29 cm v s Concentration correction term C CRP 2 23107 cm Critical doping concentration on CSP 6 101029 cm Critical doping concentration in the correction term P PCP 9231016 cm s Concentration correction of the minimum mobility a ALPP 0 719 none Exponent in the concentration factor p BETP 2 0 none Exponent in the concentration correction factor y GAMP 2 2 none Temperature factor ekponent 3 DELP 2 051044 V s Acoustic term parameter Dodo BESP 1 0 none Exponent in the saturation velocity eon VSAP 1071
72. nvolved it is convenient to introduce the discretized derivatives of the Bernoulli function for electrons again for holes the substitution u gt u should be made F AW FOI Vi cg jp PCENA 2 I h F AW S Faj Vip Heigl PAW gt 2 J where F x d By l exp x exp is the derivative of the B ernoulli function ex exp x 1 Thus we have the following expressions for the matrix elements of A w n p aj FAV a HAX Dj yj FON 1 AN Dij aij FAN Ai DPi jt FC AVI HAKI DPI A bij Fa AW FAX D i FAW 1 AXj DML MICROTEC 4 0 User s M anual 75 Device Simulation Chapter 6 AP X p L A di F Ayt AXAN j FAW AX jua djj FAY Ax Rist Fe p ALD Pi jus br s bebe mu tcd a ed A 8 i ai cae i lij Lj END ZA e j7 aj j bijt Cyt hy According to 16 the initial guess for the potential is obtained by solving Eq 22 with y i x nk j pK l taken from the previous bias W hen the carrier concentrations are fixed i e N exp Y Ph P EXP Pp v andhence Y 9 9p V are fixed updating of the potential leads to implicit quasi Fermi potential updates 6 4 References 1 M S Obrecht SIM OS two dimensional steady state simulator for M OS devices Solid State Electronics Software Survey Section vol 32 No 6 1989 2 M S Obrecht and J M G Teven BISIM a program for steady state two dimensional modeling of various bipolar devices
73. of SiDif input files A few examples of typical processing runs are presented in this section 4 9 1 M OSFET fragment Substrate with orientation 111 is doped initially with boron at 1015 cm Boron is implanted at 60 K eV and 6 101 ions cm in the whole region and then arsenic is implanted at 100 K eV and 1015 ions cm through the mask and annealed at 1000 C for 60 minutes in an inert ambient M ESH N X 220 N Y 20 X X 1 Y Y 0 7 1M 1 COMM M OSFET SUBS PH 1E12 B0 1E15 AS 1E12 0R 111 BOIM X M 22 DZ 6 E 11 EN 60 52 MICROTEC 4 0 User s M anual Chapter 4 Process Simulation ASIM XM 0 5 DZ 1 E15 EN 100 ANNE TC 1000 TM 3600 T A 600 OX 0 4 9 2 LDD MOSFET fragment Boron and arsenic are implanted as in the above example into the same substrate Then the mask is shifted by 0 35 microns and LDD arsenic is implanted at 100 KeV and 1012 ions cm Finally the wafer is annealed at 1000 C for 60 minutes MESH NX 20 N Y 20 X X 1 Y Y 0 7 1M 1 COMM LDD MOSFET SUBS PH 1E12 B0 1E15 AS 1E12 0R 111 BOIM X M 22 DZ 6 E 11 EN 60 ASIM X M 0 6 DZ 1 E15 EN 2100 ASIM X M 0 25 DZ 1 E12 EN 2100 ANNE TC 1000 T M 3600 T A 600 OX 0 4 9 3 Fragment with LOCOS Substrate is initially doped by boron at 101 cm Arsenic is implanted at 200 K eV and 101 ions cm in the left side of the region Then boron is implanted at 200 K eV and 101 ions cm through another mask in the right sid
74. ogram named SiDif has been developed 1 to compute two dimensional impurity profiles of VLSI elements that have undergone various fabrication steps T he fabrication process may include processing steps such as ion implantation or surface deposition arsenic boron or phosphorous with subsequent annealing under oxidizing or inert ambient R esulting doping profiles may be used in a straightforward manner to generate the entire structure of a semiconductor device for subsequent evaluation of l V curves in afew minutes on a PC The algorithm 2 is based on the finite difference formulation and a rectangular mesh The physical model adopted describes the diffusion process for up to three interacting charged impurities in a two dimensional domain with moving oxide boundary and impurity segregation at the Si SiO interface In the case of implantation the initial profiles of each impurity are approximated by the conventional Runge s model 12 The program is written in FORTRA N 77 and can be used on IBM AT 386 or higher with an EGA VGA SV GA adapter running under Windows Dynamic memory allocation is used in SiDif with 400 K bytes required for a 2500 node mesh T ypical process simulation requires about a minute on Pentium 100 4 2 Physical model Diffusion of charged impurities is influenced by the presence of an internal electric field The physical model for diffusivities which accounts for the influence of charged defects is taken from 4 5
75. on is used to open a SibGraf M ap window displaying the current function MICROTEC 4 0 User s M anual 29 M icroT ec Graphics SibGraf Chapter 3 Thelast two buttons are used plot the currently selected X and Y cross sections in a separate Sib Graf 2D window All subsequent cross section plots are added to the same SibGraf 2D window 3 5 Annotate All of the SibGraf 2D 3D and M ap windows have an Annotate item in their main menu Two types of annotated objects may be created Line and Text A nnotated objects are associated with the real X and Y coordinates and not with the window or screen position Therefore the annota tion objects move with respect to the window when windows are zoomed or resized When the subitem Line is chosen the user can draw a line consisting of a number of straight seg ments To continue a line from a point click the left mouse button To terminate an annotation line click the right mouse button To modify an existing Annotate L ine object first select it by clicking the left mouse button on the line Then either the whole line or any of its nodes can be moved to the desired position with the left mouse button Clicking the left mouse button anywhere away from the line will terminate the modification mode W hen the subitem Text is chosen a window will appear where the user can type the required text and choose whether a border around the text is shown W hen the OK button is pressed the text will be plac
76. onents etc See Section M icroTec Graphics SibGraf on page 31 for more informa tion on the M icroTec graphics Project Settings Page To modify project settings click on the Project Settings tab The other page of the main M icro Tec menu will appear showing a Project Tree containing directives subdirectives and parame ters as in figure 2 2 Click the left mouse button on a folder symbol to open it Double click the left mouse button on a parameter to edit it To modify the tree structure click a directive subdirective parameter with the left and then the right mouse button A menu pops up allowing you to Delete Copy Insert or Add an entry If you select Delete the current entry will be deleted If you select Copy a new copy of the current entry will be added at the end of the project tree Selecting Insert or Add brings up a new window showing a list of entries that may be added at this stage Select one of them and click OK Newly added parameters are given default values Double clicking a parameter brings up an edit window showing the current parameter value and a brief parameter description Edit the 16 MICROTEC 4 0 User s M anual Chapter 2 M icroT ec User Interface parameter value in the text box and click OK There are different types of directives in MicroTec unique or non unique and B soa mandatory or optional For example ie ee A the Photogeneration directive
77. onplanar devices IEEE Trans Computer A ided Design vol 7 pp 1164 1170 November 1988 11 D L Scharfetter H K Gummel Numerical simulation of Read diode oscillator IEEE Trans Electron Devices vol 16 pp 64 70 1969 12 M S Obrecht A modification of CCG method for solving discretized continuity equations for semiconductor device at any voltages Submitted to Solid State Electronics 13 H A Van Der Vorst Bi CGSTAB afast and smoothly converging variant of Bi CG for the solution of nonsymmetric linear systems SIAM Journ Sci Stat Comput vol 13 pp 631 644 March 1992 14 H K Gummel A self consistent iterative scheme for one dimensional steady state transis tor calculations IEEE Trans Electron Devices vol 11 pp 455 465 1964 15 A DeMari An accurate numerical steady state one dimensional solution of the p n junc tion Solid St Electronics vol 11 p 33 58 1968 16 M S Mock A time dependent numerical model of the insulated gate field effect transis tor Solid State Electronics vol 24 pp 959 966 1981 6 5 Running SemSim Torun SemSim from the M icroT ec shell Select a project corresponding to SemSim or add a new project by selecting SemSim method in the M ethod window Edit parameters by switching to Project Settings page of the in the main M icroTec menu Click Run button To run SemSim outside the M icroT ec the command line should look as follows
78. parameters Name Default Units Description TC 1000 C Temperature of oxidation centigrade TM 1000 S Time of oxidation in seconds TAU 100 S Initial time step in seconds T he recommended value is 30 s for a temperature of 1200 C 100 s for 1100 C 200 s for 1000 C and 500 s for 900 C and lower For an accurate eval uation on a fine mesh the recommended value is 2 10 times lower than the one above Use a smaller TAU if the number of nonlinear iterations exceeds 7 OX 1 none Typeof annealing atmosphere 1 dry oxygen 2 wet ambient POX 1 Atm Pressure of the oxidizing ambient oxygen or vapor XO 0 um Position of the oxidation mask The oxide grows in the region from 0 to XO if XO is positive and from XO to X X if XO is negative To get a uniform oxide make X O a few times greater than XX U0 0 001 um Initial uniform oxide thickness microns It affects the rate of the oxide growth COMM Comm none Comment line ANNE annealing parameters Name Default Units Description TC 1000 IC Temperature of annealing centigrade TM 1000 S Time of annealing in seconds 46 MICROTEC 4 0 User s M anual Chapter 4 Process Simulation Name Default Units Description TAU 100 S Initial time step in seconds T he recommended value is 30 s for a temperature of 1200 C 100 s for 1100 C 200 s for 1000 C and 500 s
79. rective OHMI Ohmic electrode Name Default Units Description NAME ohmic none Electrode name The first letter will be used for current and voltage subscripts NUM 1 none Electrode number Important when setting initial voltages and voltage step in I V data LOC 1 none Location of the electrode 1 is on the top and 2 is on the bot tom of the domain XLT 0 um Left electrode edge coordinate XRT 1 um Right electrode edge coordinate MICROTEC 4 0 User s M anual 83 Device Simulation Chapter 6 GATE Gate electrode Name Default Units Description NAME gate none Electrode name The first letter will be used for current and voltage subscripts NUM 1 none Electrode number Important when setting initial voltages and voltage step in V data LOC 1 none Location of the electrode 1 is on the top and 2 is on the bot tom of the domain XLT 0 um Left electrode edge coordinate XRT 1 um Right electrode edge coordinate TOX 0 02 um Gate oxide thickness XQS 0 01 um Location of the Gaussian Qss under the gate AQS 0 01 um Exponent of the Gaussian Qss under the gate QSH 0 cm Homogeneous component of the Qss under the gate QSG 0 cm Gaussian component of the Qss under the gate VSN 11015 cm s Electron recombination velocity under the gate VSP 11015 cm s Holerecombination velocity under the ga
80. rker is dis played in the status bar Figure 3 6 SibGraf 2D window showing The buttons logx LE rmm v2 Jaza logY absX and absY are used to switch to and from logarithmic and absolute scale on either the X or Y axis The second last button marked Del deletes the selected curve from the plot The last button switches into the tracer mode When in tracer mode two perpendicular lines fol low the mouse along the curve The status bar displays the x and y values of the intersection point of the two lines This allows you to trace any part of the graph including points that fall between markers as in figure 3 2 2D Data File Structure This section describes the format of a data file that can be loaded by the Load selection under the File menu By default the program looks for files with an extension of 2d where is any character Each data file contains sets of data which are referred to as families Each family is anumber of data columns each with the same number of entries rows After the file is loaded the user may choose which column is the X axis and which column or columns will be shown on the Y axis The user may also choose to plot a product or ratio of any two columns on the Y axis It allows plotting of such quantities as current gain B lc lg etc 24 MICROTEC 4 0 User s M anual Chapter 3 M icroT ec Graphics SibGraf 3 3 SibGraf M ap Edit M enu The user has five menu
81. s modelling SUPREM III IEEE Trans Electr Dev v ED 30 p 1439 1983 B E Deal and A S Grove General relationship for the thermal oxidation of silicon J Applied Physics vol 36 p 3770 1965 K T anigushi et al Two dimensional computer simulation models for MOS LSI fabrication processes IEEE Trans Electr D ev v ED 28 p 574 1981 R B Fair and J C Tsai Theory and measurement of boron segregation in SiO during oxi dation J Electrochem Soc vol 125 p 2050 1978 V I K oldyaev V A M oroz et al Two dimensional simulation of the doping and oxidation of silicon Optoelectronics Instrumentation and Data Processing Avtometria No 3 p 50 1988 A S Grove et al Redistribution of acceptor and donor impurities under oxidation of sili con J Applied Physics vol 35 p 2695 1964 H Runge Distribution of implanted ions under arbitrarily shaped mask Phys Stat Sol v 39 a p 595 1977 G Schneider M Zedan A modified strongly implicit procedure for the numerical solution of field problem Numerical Heat Transfer vol 4 p 1 1981 H A Van Der Vorst Bi CGSTAB afast and smoothly converging variant of Bi CG for the solution of nonsymmetric linear systems SIAM Journ Sci Stat Comput vol 13 pp 631 644 March 1992 S Furukawa H M atsumura and H Ishiwara Theoretical Considerations on L ateral Spread of Implanted lons Jap J Apll Phys vol 11 No
82. s zero For boundary segments underneath gate contacts the electric field is approximated by the formula _ Vg er Ws E EY ha 6 29 where Va eff Vg appr 9g hg is the oxide thickness and y is the local potential value at the interface 6 2 5 M obility M odels Several options for concentration and field dependent mobility models are available In BiSim the concentration and field dependent mobility is taken in a form similar to 8 a T ys min 1 Up 300 Hp E 72 Hs p N Ep I G surf n i ELENE e S 1 E 6 30 1 55 i NI E eny 300 Wer zd Ms Ep Bo Br M Es ED ns AN E 14 7205 7 6 31 sat n A nd analogous expression for holes In SiM OS either the Y amaguchi expression 9 or the recent expression by Lombardi et al 10 may be used In the first case 9 SR D V uj EA uA Es ED m E 14 t A 6 32 G ES Vs _ Vc 1 1 N 2 a N Ey ug 1 7 1 taj i 6 33 NS MICROTEC 4 0 User s M anual 69 Device Simulation Chapter 6 where and are corresponding longitudinal and transverse components of the electric field with respect to the current direction In the second case 10 the mobility includes three terms etal it 6 34 where is the carrier mobility limited by the surface acoustic phonon scattering u is the carrier mobility in the bulk silicon and u is the carrier mobility limited by the surface roughness scattering These terms are described
83. semsim project inp File inst pas must be present in the directory where M icroT ec is installed There are two output files generated by SemSim 1 A file with two dimensional distributions It has the extension 3D 2 A file with l V data It has the extension 2D Thesetwo files may be displayed by M icroT ec graphics tools Click on the 2D or 3D button in the M icroT ec main menu to plot the results MICROTEC 4 0 User s M anual 77 Device Simulation Chapter 6 Refer to sections below for the description of the input file 6 6 SemSim input file SemSim main input file contains directives subdirectives and parameters Each directive contains subdirectives or parameters starts with the directive key followed by and should be ended by Each subdirective contains parameters separated by spaces or commas They start with the subdirective key followed by and ended by Input is closed by all directives after are ignored 6 6 9 SemSim list of directives Directive subdirective tree looks as follows B AS Basic directives MESH Mesh and domain parameters SOLV Numerical solution parameters MODE Physical models 3DOP Analytical doping data DOPA Doping well DOPN Numerical doping data from file ELE Electrodes OHM I Ohmic electrode GATE Gate electrode SCHO Schottky electrode V D IV data or a set of I V curves VDA IV curve M AT Material
84. ser can choose to remove either this label or all contour lines at the corresponding level from the plot The location of a label can be changed by dragging the label with the left mouse button If the label is moved completely out of the plot area it becomes invisible although it still exists and will appear if for example the Figure 3 9 Contour map Unzoom function is used A new contour line may be added to the graph by right clicking anywhere in the graph area The new contour line will run through the point where the mouse was clicked Right clicking on a contour label brings up a menu allowing the deletion of the label or of the entire contour line M ap Status Bar The status bar is the strip at the bottom of the plot window If probe mode is off the first row of three numbers in the status bar show the values of the X and Y coordinates of the current cross sections and the Z value at the point of their intersection If probe mode see below is on the first row of three numbers show the values of the X Y and Z coordinates at the current mouse position The bottom row of numbers always show the mesh step numbers of the current X and Y cross sections and the overall dimension of the grid M ap Tool Bar The tool bar is the line of buttons just below the main menu and just above the plot window The first four buttons are used to select current X and Y cross sections This can also be done by using the arrows on the keyboard
85. sing the discretized continuity equation to estimate the derivatives ou and g We use the expressions n exp v o v P explop w v where the dependencies w pp y are estimated from the discretized continuity equation The changes in w Qo caused by the changing v value during the Poisson iteration are estimated The approach leads to the following form for the linearized discretized Poisson equation 6 54 k Arm Jj j k 1 k 1 k 1 Ksdoo k ns k 1 em nni PO Np NJ y HO Fo pi DOG Wis EDI i 6 55 where MICROTEC 4 0 User s M anual 73 Device Simulation Chapter 6 Finn d n Aj In n and a iD J dw dv Obviously af a 1 when nif pj 0 and in this case we arrive dv dvi at the conventional Gummel scheme Note also that the expressions for updating the carrier concentrations become ny S nyi exper ut vii and k k k k pi poi exp oj i Vig D The discretized continuity equations are used to estimate a and o We express n j and pij using equations 8 11 obtaining n n n de p ia Ojea Co ji Oj 6 56 ij 5 n i e j p p p p p 7 2i Pi a j Pi Pi v Ci Pin rst CLP jn 657 e Lj where we have neglected the generation recombination term R G j We use equations 19 20 to evaluate az and ox from their derivatives with respect to vi The assumptions about the carrier density dependencies on y are particularly important As show
86. te FIM 4 25 eV Work function of the gate metal Parameters 5 s Ags O54 Qs define slow surface states or fixed surface charge at the Si Si02 interface as follows Qss Qsyt Oscexp x Er Ags SCHO Schottky electrode Name Default Units Description NAME schottky none Electrode name The first letter will be used for current and voltage subscripts NUM 1 none Electrode number Important when setting initial voltages and voltage step in IV data 84 MICROTEC 4 0 User s M anual Chapter 6 Device Simulation Name Default Units Description LOC 1 none Location of the electrode 1 is on the top and 2 is on the bot tom of the domain XLT 0 um L eft electrode edge coordinate XRT 1 um Right electrode edge coordinate VSN 1 10 cm s Electron recombination velocity at the interface VSP 1 10 cm s Hole recombination velocity at the interface FIB 0 eV Potential barrier the difference between the Fermi potential of the contact material and that of the intrinsic semiconductor 6 6 15 AVD IV data directive This directive may include any number of I V DA subdirectives Each I V DA subdirective defines one IV curve for which one the contact voltages is ramped IVDA IV Curve Name Default Units Description TEXT none Text to be output to the I V data file NUMC 1 none Number of the
87. tep A A 4 r r E l mW RETE es Ut Ay is the discretized L aplace operator hi 2 2 ja r n WA 1i hr AmV i 7 Visi j7 Vi V j Vi 1 t jr Vip AV jr Vi j 1 J h h 1 f j 1 6 44 Ap Ap represent the operators for the discretized continuity equations for electrons and holes respectively _ an n n n DN j ajni PO a 8 1j C jia JA al mp MEC ET jt d fli jaa 6 45 J l MICROTEC 4 0 User s M anual 71 Device Simulation Chapter 6 S p p p p Ag OP j 8j Pi agt Di Pi j 17 C1 Pig Ci Die st Ti Pi Y gt 6 46 To reduce the number of formulae and indices involved we introduce the discretized B ernoulli functions For electrons n rm AV u r B Ay B Y y A AS B Ay 647 nl AW Bn Wis j7 Wid 1 jh exp Ay 1 isijh ay ean B Ay B P E RT ETT DERE nS See Oe ijs n explo D7 it MUR P e where u j and u 1 are the electron mobilities at the midpoints 5 hits AV is the conventional Bernoulli exp Ay 1 between the mesh nodes and B Ay function Corresponding expressions for holes have exactly the same form with the substitution u gt u The expressions for the matrix coefficients of A A now take a very simple form p ajj By AV 1 AX s Dj BAV 1 FAX 6 49 cij By AV Ax dj BAY Ax 6 50 ap BAV i7 Ax s Of BAW 7 AXj 3 6 51 cj By Ay Ax d By AV AX 6
88. ting Started 1 1 Introduction Semiconductor device modeling has become a standard design tool in the microelectronics indus try A few years ago this modeling was performed primarily on supercomputers At the present time a number of commercial 2D process and device simulators are available mostly for UNIX based workstations Normally they require tens of Mbytes of memory even for modest sized meshes Increasing performance and widespread availability of IBM PCs and compatibles encourage the development of software tools that can be used for 2D modeling of semiconductor devices and processes with a rather low memory capacity and speed of computation Recently a few efficient programs were developed for two dimensional semiconductor process device simulation on a PC which have now been integrated together into a package named M icroTec MicroTec The Semiconductor TCAD Calculator MicroTec allows 2D silicon process modeling including implantation diffusion and oxidation and 2D steady state semiconductor device simulation like MOSFET DMOS JFET BJT IGBT Schottky photosensitive devices etc Although M icroTec is significantly simplified compared to widely available commercial simulators it nevertheless is a very powerful modeling tool for industrial semiconductor process device design In many instances M icroTec outperforms exist ing commercial tools and it is remarkably robust and easy to use M icroTec is especially attractive for e
89. uniform mesh is used M ESH N X 25 NY 38 X X 22 Y Y 3 5 1M 0 A X 1 E 5 AY 1 COM M Buried layer example SUBS PH 1E12 B0 1E16 AS 1E12 0R 111 ASIM X M 10 EN 2300 DZ 1E 15 ANNE TC 1000 T M 3600 T A 600 OX 0 EPIT TH 2 PH 1 E 12 B O 1 E 12 A S 1 E15 TC 1200 T M 600 T A 150 BOIM X M 1 DZ 1 E12 EN 100 ANNE TC 1000 T M 3600 T A 600 OX 0 4 9 6 Emitter region To simulate emitter formation in the large fragment simulated in the previous example only its small upper region is considered The substrate is doped by arsenic at 1015 cm with boron implanted at 100 KeV and 1012 ions cm and arsenic implanted at 60 KeV and 101 ions cm through the mask into the left half of the region The wafer is then annealed for 1 hour at 1000 C The mesh is nonuniform in order to resolve a steep initial arsenic profile near the surface M ESH N X 15 NY 20 X X 1 Y Y 1 1 1M 0 AX 1 E 5 AY 1 COMM Emitter region SUBS PH 1E12 B0 1E12 AS 1E15 OR 111 BOIM X M 2 DZ 1 E12 EN 2100 ASIM XM 0 5 DZ 1 E15 EN 60 54 MICROTEC 4 0 User s M anual Chapter 4 Process Simulation ANNE TC 1000 TM 3600 T A 600 OX 0 MICROTEC 4 0 User s M anual 55 Process Simulation Chapter 4 56 MICROTEC 4 0 User s M anual DEVICE FORMATION MICROTEC 4 0 User s M anua 57 Chapter 5 Device formation 5 1 Introduction M ergl C provides an interface between the process simulation tool SiDif and the dev
90. ying and symmetrizing fragments simulated by SiDif Black 3D Output button means that the result has been successfully computed and you may plot the output doping profiles by clicking on this button If itis grey click Run button to perform process simulation and after the result has been computed the button becomes black 4 6 SiDif input file SiDif main input file contains directives and parameters Each directive starts a group of parameters separated by spaces or commas and ended by The computational domain and the mesh are the same for all the processing steps The last step must be ended by All directives after will be ignored Note Only one step with the oxidizing annealing is allowed in the present version of SiDif Only implantation deposition and inert annealing may be simulated after the oxide formation All the directives are of two types basic directives and model parameter directives 4 6 1 SiDif Directive L st SiDif basic directives MESH computational domain and mesh parameters SUBS substrate parameters SOLV numerical solution control PHDE phosphorus deposition BODE boron deposition ASDE arsenic deposition 42 MICROTEC 4 0 User s M anual Chapter 4 Process Simulation PHIM phosphorus implant BOIM boron implant ASIM arsenic implant OXID oxidation parameters ANNE annealing parameters EPIT epi layer formation SiDif model parameter directiv

Manual - Siborg Systems Inc.

Contents

Download Pdf Manuals

Related Search

Related Contents