Appendix B: Material Systems
Contents
1. B 18 SILVACO International Material Systems Insulators The default material parameters for insulator materials are given in the following sections As noted in the Semiconductors Insulators and Conductors section the only parameter required for electrical simulation in insulator materials is the the dielectric constant Thermal and optical properties are required in GIGA and LUMINOUS respectively Insulator Dielectric Constants Table B 22 Default Static Dielectric Constants of Insulators Material Dielectric Constant Vacuum 1 0 Air 1 0 Ambient 1 0 Oxide 3 9 Si02 3 9 Nitride Ted SiN a5 Si3N4 7 55 Sapphire 12 0 Insulator Thermal Properties Table B 23 Default Thermal Parameters for Insulators Material Thermal Capacity J cm Thermal Conductivity deg cm W Reference Vacuum 0 0 0 0 Air 1 0 0 026 7 Ambient 1 0 0 026 7 Oxide 3 066 0 014 4 Si02 3 066 0 014 4 Nitride 0 585 0 185 4 SILVACO International B 19 ATLAS User s Manual Volume 2 Table B 23 Default Thermal Parameters for Insulators Material Thermal Capacity J cm Thermal Conductivity deg cm W Reference SiN 0 585 0 185 4 Si3N4 0 585 0 185 4 Sap phire B 20 SILVACO International Material Systems Optical Properties The default values for complex index of refraction in LUMINOUS are interpolat2. The default values for the s ELB impact ionization coefficients used for SiC are given in Table B 17 Table B 17 Impact lonization Coefficients for SiC Parameter Value EGRAN 0 0 BETAN 1 0 BETAP 10 AN1 1 66x10 AN2 1 66x10 BN1 1 273x10 BN2 Weise ane AP 1 5 18x10 AP2 5 18x10 BP1 1 4x107 BP2 1 410 SiC Thermal Parameters The default thermal parameters used for both 6H and 4H SiC are shown in Table B 18 Table B 18 Default Thermal Parameters for SiC Parameter Value 4H SiC 6H SiC TCA 0 204 0 385 HCA 0 0 B 14 SILVACO International Material Systems Miscellaneous Semiconductors The remainder of the semiconductors available have defined default parameter values to various degrees of completeness The following sections describe those parameter defaults as they exist Since many of the material parameters are not available at this time it is recommended that care be taken in using these materials It is important to make sure that the proper values are used Note The syntax MOD Miscellaneous Semiconductor Band Parameters EL PRINT can be used to echo the parameters used to the run time output Table B 19 Band Parameters for Miscellaneous Semiconductors Material Eg 0 eV Eg 300 eV Oo B me my xyeV
3. AlP 9 8 AlAs 12 0 AlSb TIO B 16 SILVACO International Material Systems Table B 20 Static Dielectric Constants for Miscellaneous Semiconductors Material Dielectric Constant GaSb omer InSb 18 0 ZnS 8 3 ZnSe 8 1 Cds 8 9 CdSe 10 6 CdTe T09 HgS HgSe 25 0 HgTe 20 PbS 170 0 PbSe 250 0 PbTe 412 0 SnTe SCN GaN 9 5 AIN 9 14 InN 1932 6 BeTe Miscellaneous Semiconductor Mobility Properties Table B 21 Mobility Parameters for Miscellaneous Semiconductors Material MUNO cm2 Vs MUPO cm2 Vs VSATN cm s VSAT cmcm s Ge 3900 0 a 1900 0 b Diamond 500 0 300 0 2 0x10 SiC a 330 0 300 0 2 0107 SiC b 1000 0 50 0 2 0x107 AlP 80 0 SILVACO International ATLAS User s Manual Volume 2 Table B 21 Mobility Parameters for Miscellaneous Semiconductors Material MUNO cm2 Vs MUPO cm2 Vs VSATN cm s VSAT cmcm s AlAs 1000 0 100 0 A1lSb 200 0 550 0 GaSb 4000 0 1400 0 InSb 7800 0 750 0 ZnS 165 0 5 0 ZnSe 100 0 16 Cds 340 0 50 0 CdSe 800 0 CdTe 1050 0 100 0 HgS HgSe 5500 0 HgTe 22000 0 100 0 PbS 600 0 700 0 PbSe 1020 0 930 0 PbTe 6000 0 4000 0 SnTe ScN GaN 400 0 8 0 2 0x10 AlN 14 0 InN 3000 0 BeTe Notes a Uses Equation B 4 with TMU N 1 66 b Uses Equation B 4 with TMUP 2 33
4. following section of the input deck illustrates how these parameter defaults may be modified new material AlInGaP ATERIAL MATERIAL InGaAsP SRH ATERIAL MATERIAL InGaAsP TAUNO 1 1le 9 TAUP0 2 3e 8 Auger ATERIAL MATERIAL InGaAsP AUGN 5 8e 30 AUGP 1 1le 31 Optical material material InGaAsP COPT 1 7e 30 B 22 SILVACO International Material Systems Thermoconductivity MATERIAL MATERIAL InGaAsP TC A 2 49 Heat capacity MATERIAL MATERIAL InGaAsP HC A 1 9 T SILVACO International B 23 ATLAS User s Manual Volume 2 B 24 SILVACO International
5. is defined as an electrode is then considered to be a conductor region This is typical for polysilicon gate electrodes Insulators In insulator materials only the Poisson and lattice heat equations are solved Therefore for isothermal simulations the only parameter required for an insulator is dielectric permittivity defined using MATERIAL PERM lt n gt Materials usually considered as insulators eg SiO2 can be treated as semiconductors using BLAZE however all semiconductor parameters are then required Conductors All conductor materials must be defined as electrodes Conversely all electrode regions are defined as conductor material regions If a file containing regions of a material known to be a conductor are read in these regions will automatically become un named electrodes As noted bellow if the file contains materials that are unknown these region will become insulators During electrical simulation only the electrode boundary nodes are used Nodes that are entirely within an electrode region are not solved Any quantities seen inside a conductor region in TONY PLOT are spurious Only optical ray tracing and absorption for Luminous and lattice heating are solved inside of conductor electrode regions SILVACO International B 1 ATLAS User s Manual Volume 2 Unknown Materials If a mesh file is read containing materials not in Table B 1 these will automatically become insulator regions with a relative perm
6. 300 dielectric permitivity PERMITIVITY and electron and hole mobilities MUN and MUP For bipolar devices certain recombination parameters should also be defined such as lifetimes TAUN and TAUP radiative recombination rates COPT and Auger coefficients AUGN and AUGP For devices with variations in material composition certain band edge alignment parameters should also be defined either electron affinity AFFINITY or edge alignment ALIGN If impact ionization is considered the impact ionization coefficients should also be defined As an example consider the case where the user is simulating a device with an AlInGaP region Consulting table B 1 we see that this material system is not defined in ATLAS We then choose a materal that is defined in ATLAS which has default material parameters that best approximate the material parameters of the new material In this case we choose InGaAsP since at least for example purposes we feel that this material is closest to the AlTInGap Next we must specify InGaAsP as the material of the region s that is are composed of AlInGap This can be done either on the REGION statement if the structure is defined in ATLAS syntax or from the material menu when the region is defined in DEVEDIT Supposing that we are satisfied with the default values of the parameters from the minimum set discussed above and that we are principally concerned with the recombination and heat flow parameters defaults the
7. Appendix B Material Systems Overview ATLAS understands a library of materials for reference to material properties and models of various regions in the semiconductor device These materials are chosen to represent those most commonly used by semiconductor physicists today Users of BLAZE or BLAZE3D will have access to all of these materials S PISCES or DEvICE3D users will have only access to Silicon and Polysilicon S PISCES is designed to maintain backward compatibility with the standalone program SPISCES2 version 5 2 In the SPISCES2 syntax certain materials could be used in the REGION statement just by using their name as logical parameters This syntax is still supported Semiconductors Insulators and Conductors All materials in ATLAS are strictly defined into three classes as either semiconductor materials insulator materials or conductors Each class of material has particular properties to which all users should be aware Semiconductors All equations specified by the user s choice of models are solved in semiconductor regions All semiconductor regions must have a band structure defined in terms of bandgap density of states affinity etc The parameters used for any simulation can be echoed to the run time output using MODELS PRINT For complex cases with mole fraction dependent models these quantities can be seen in Tonyplot by specifying OUTPUT BAND PARAM and saving a solution file Any semiconductor region that
8. GAAS yP y System InGaAsP Thermal Parameters The default material thermal models for InGaAsP assumes lattice matching to InP The material density is then given by p 4 791 0 575y composition 0 138y composition The specific heat for nGaAsP is given by C 0 322 0 026y composition 0 008y composition The thermal resistivities of InGaAsP are linearly interpolated from Table B 15 Table B 15 Thermal Resistivities for InGaAsP Lattice Matched to InP Composition Fraction y Thermal Resistivity deg cm w 0 0 L 47 0 1 7 05 0 2 11 84 0 3 15 83 0 4 19 02 0 5 21 40 0 6 22 96 ies 23471 0 8 23 63 0 9 22T 1 0 20 95 The default thermal properties of the binary compounds in the InGaAsP system are given in Table B 16 Table B 16 Default Thermal Properties of InP InAs GaP and GaAs Material Thermal Capacity J cm3 Thermal Resistivity deg cm W InP 1 543 1 47 InAs 1 994 3 70 GaP 1 292 1 30 GaAs Ts 3 8 LED B 12 SILVACO International Material Systems The default thermal properties for the terniary compounds in the InGaAsP system n 7 GagyAs IN z x GAgyP INASP z y and GaAsiy P z y are given as a function of composition fraction by linear interpolations from these binary compounds SILVACO International B 13 ATLAS User s Manual Volume 2 Silicon Carbide SiC SiC Impact lonisation Parameters
9. Silicon Poly silicon Ge 0 7437 A 77 1074 235 0 0 2225 0 2915 4 0 Diamond 5 45 4 77x1074 0 0 a b TaZ 6H SiC 2 9 2 9 0 0 0 0 0 454 0 33 4H Sic 22 22 0 0 0 0 0 41 0 165 A1P 2 43 2 43 0 0 0 0 AlAs 2 16 2 16 0 0 0 0 A1Sb 1 6 2 69x1072 2 788 c 0 4 GaSb 0 81 3 329x1074 27 6622 c 0 24 3 65 InSb 0 235 gt 81721074 90 0003 0 014 0 4 4 06 ZnS 3 8 3 8 0 0 0 0 0 4 4 59 ZnSe 2 58 2 58 0 0 0 0 0 1 0 6 ZnTe 2 28 0 0 0 0 0 1 0 6 4 09 Cds 2 53 2 53 0 0 0 0 0 21 0 8 3 5 CdSe 1 74 1 74 0 0 0 0 0 13 0 45 4 5 CdTe 1 5 1 5 0 0 0 0 0 14 0 37 HgS 25 2 5 0 0 0 0 4 28 HgSe HgTe SILVACO International B 15 ATLAS User s Manual Volume 2 Table B 19 Band Parameters for Miscellaneous Semiconductors Material Eg 0 eV Eg 300 eV 0 B Me my xyeV PbS 03T 0 37 0 0 0 0 0 25 0 25 PbSe 0 26 0 26 0 0 0 0 0 33 0 34 PbTe 0 29 0 29 0 0 0 0 0 17 0 20 4 6 SnTe 0 18 0 18 0 0 0 0 ScN 2 15 2 15 0 0 0 0 GaN 3 45 3 45 0 0 0 0 0172 0 259 A1N 6 28 6 28 0 0 0 0 0 314 0 417 InN 1 89 1 89 0 0 0 0 0 11 OT BeTe 257 2257 0 0 0 0 Notes a Nc300 5 0x1018 b Nv300 1 8x10 9 c m X 0 39 m G 0 09 Nc Nc X Nc G d m G 0 047 m L 0 36 Nc Nc G Nc L Miscellaneous Semiconductor Dielectric Properties Table B 20 Static Dielectric Constants for Miscellaneous Semiconductors Material Dielectric Constant Ge 16 0 Diamond 5 25 6H SiC a 9 66 4H SiC b 9 72
10. ed from tables from the Handbook of Optical Constants first and second editions Rather than print the tables here the ranges of optical wavelengths for each material are listed in Table B 24 Table B 24 Wavelength Ranges for Default Complex Index of Refraction Material ae Composition Fraction Wavelengths microns Silicon 300 NA 0 0103 2 0 AlAs 300 NA 0 2213 50 0 GaAs 300 A 0 0 0 9814 InSb 300 NA 0 2296 6 5 InP 300 NA 0 1689 0 975 Poly 300 A 0 1181 18 33 SiO2 300 NA 0 1145 1 7614 Note The parameter INDEX CHECK can be added to the SOLVE statement to list the values of real and imaginary index being used in each solution SILVACO International B 21 ATLAS User s Manual Volume 2 User Defined Materials The current version of ATLAS does not directly support user defined materials A simple workaround can be done using the already existing user specifications This workaround is based on the use of an already existing material name and modifying the material parameters as appropriate In ATLAS material names are defined to give the user a reasonable set of default material parameters Any of these defaults can be overriden using the MATERIAL IMPACT MODEL and MOBILITY statements The key to defining new materials is choosing a material name that is defined in ATLAS then modifying the material parameters of that material to match the user materia
11. ittivity of 3 9 All user defined materials from ATHENA irrespective of the material name chosen by the user will also become such insulator materials B 2 SILVACO International Material Systems ATLAS Materials ATLAS materials are listed in Table B 1 below Table B 1 The ATLAS Materials Single Element Semiconductors Silicon Poly Germanium Diamond Binary Compound Semiconductors GaAs gt GaP CdSe SnTe SiGe InP CdTe ScN a Sic InSb HgS GaN b Sic InAs HgSe AIN AlP ZnS HgTe InN AlAs znse PbS BeTe AlSb ZnTe PbSe GaSb Cds PbTe Ternary Compound Semiconductors AlGaAs InGaAs InGaP GaSbP GaSbAs InGaN InAlAs InAsP AlGaN Quaternary Compound Semiconductors InGaAsP InGaNAs AliInNAs InAlAsP AlGaAsP InGaNP AlInNP AlGaAsSb AlGaNAs InAlGaAs GaAsP HgCdTe InAlGaN AlGaNP InAlGaP SILVACO International B 3 ATLAS User s Manual Volume 2 Insulators Vacuum Oxide Nitride Si3N4 Air SiO2 SiN Sapphire Ambient Conductors Polysilico Palladium TiW TaSi 2 Aluminum Cobalt Copper PaSi Gold Molybdenum Tin PtSi Silver Lead Nickel MoSi AlSi Iron WSi ZYSi Tungsten Tantalum TiSi A1Si Titanium AlSiTi NiSi Conductor Platinum AlSiCu CoSi Contact Notes The material models and parameters of Silicon are identical to those of S PISCES version 5 2 Users should be aware that although these band parameters may be physically inaccurate compared to bu
12. l Here it is best to choose a material that has default parameter values that might best match the user material while being sure to choose a material that is not already in the user device Next the user must associate this material name with the device regions where the new material is present This is done by either specifying the chosen material name on the appropriate REGION statements when the device is defined in the ATLAS syntax or choosing the material name from the materials menu when defining the region in DEVEDIT Next the user should modify the material statements using MATERIAL IMPACT MOBILITY and MODEL statements When doing this the MATERIAL parameter of the given statement should be assigned to the chosen material name For materials with variations in composition fraction the user should choose a defined material with X and or Y composition fractions i e a terniary or quaterniary material The user may also find it convenient to use C interpreter functions to define the material parameters as a function of composition The C interpreter functions that are useful for this approach are F MUNSAT F MUPSAT F BANDCOMP F VSATN F VSATP F RECOMB F INDEX F BGN F CONMUN F CONMUP F COPT F TAUN F TAUP F GAUN andF GAUP In defining new materials there exists a minimum set of parameters that should be defined This set includes bandgap EG300 electron and hole density of states NC300 and NV
13. lk silicon measurements most other material parameters and models are empirically tuned using these band parameters Polysilicon is treated differently depending on how it is used In cases where it is defined as an electrode it is treated as a conductor It can also be used as a semiconductor such as in a polysilicon emitter bipolars The composition of SiGe is the only binary compound that can be varied to simulate the effects of band gap varia tions Conductor names are only associated with electrodes They are used for the specification of thermal conductivities and complex index of refraction and for display in TonyPlot Rules for Specifying Compound Semiconductors The rules for specifying the order of elements for compound semiconductors are derived from the rules used by the International Union of Pure and Applied Chemistry 1 Cations appear before anions 2 When more than one cation is present the order progresses from the element with the largest atomic number to the element with the smallest atomic number 3 The order of anions should be the in order of the following list B Si C Sb As P N H Te Se S At Br Cl O and F 4 Thecomposition fraction x is applied tothe cation listed first 5 Thecomposition y is applied to the anion listed first To accomodate popular conventions there are several exceptions to these rules B 4 SILVACO International Material Systems SiGe The composition fraction
14. model and their coefficients are given in Chapter 3 Table B 4 contains the silicon and polysilicon default values for the low field constant mobility model Table B 4 Lattice Mobility Model Defaults for Silicon and Poly Material MUN MUP TMUN TMUP cm2 Vs cm2 Vs Silicon 1000 0 500 0 1 5 125 Poly 1000 0 500 0 15 12 5 B 6 SILVACO International Material Systems Table B 5 contains the silicon and polysilicon default values for the field dependent mobility model Table B 5 Parallel Field Dependent Mobility Model Parameters for Silicon and Poly Material BETAN BETAP Silicon 2 1 Poly 2 1 Silicon and Polysilicon Bandgap Narrowing Parameters The default values used in the bandgap narrowing model for Sllicon and Polysilicon are defined in Table B 6 Table B 6 Bandgap Narrowing Parameters for Silicon and Poly Statement Parameter Defaults Units MATERIAL BGN E 6 92x1073 V MATERIAL BGN N 1 3x1017 anes MATERIAL BGN C O 5 Silicon and Polysilicon Recombination Parameters The default parameters for Schockley Read Hall recombination are given in Table B 7 Table B 7 SRH Lifetime Parameter Defaults for Silicon and Poly Material TAUNO s TAUPO s NSRHN cm NSRHP cm Silicon O AO 1 0x107 5 0x101 5 0x1016 Poly 1 0x107 1 0x107 5 0x1016 5 0x101 The defaul
15. rnational B 9 ATLAS User s Manual Volume 2 The Al Gay1 As Material System AlGaAs Recombination Parameters The default recombination parameters for AlGaAs are given in Table B 12 Table B 12 Default Recombination Parameters for AlGaAs Parameter Value Equation TAUNO 1 0x1072 3 213 TAUPO 1 0x1078 3 213 COPT 1 5x1072 3 226 AUGN 5 0x1073 3 227 AUGP 1 0x1073 3 227 GaAs and AlGaAs Impact lonization Coefficients The default values for the s AlGaAs uses the same values as GaAs Table B 13 Impact lonization Coefficients for GaAs Parameter Value EGRAN 0 0 BETAN 1 82 BETAP 1 75 EGRAN 0 0 AN1 1 889x10 AN2 1 889x10 BNI 5 75x10 BN2 5 75x10 AP1 2215 RIO AP2 2 215x10 BP1 6 57x10 BP2 6 57x10 ELB impact ionization coefficients used for GaAs are given in Table B 13 B 10 SILVACO International Material Systems AlGaAs Thermal Parameters The default thermal parameters used for AlGaAs are given in Table B 14 Table B 14 Default Thermal Parameters for GaAs Parameter Value TCA D527 HCA 1 738 GaAs Effective Richardson Coefficients The default values for the effective Richardson coefficients for GaAs are 6 2875 A cm2 K2 for electrons and 105 2 A cm2 K2 for holes SILVACO International B 11 ATLAS User s Manual Volume 2 The Ing x
16. t parameters for Auger recombination are given in Table B 8 Table B 8 Auger Coefficient Defaults for Silicon and Poly Material AUGN AUGP Silicon 8 3x1073 1 8x1073 Poly 8 3x107 1 8x10731 SILVACO International B 7 ATLAS User s Manual Volume 2 Silicon and Polysilicon Impact lonization Coefficients The default values for the SELB impact ionization coefficients are given in Table B 9 Table B 9 Impact lonization Coefficients for Silicon and Poly Parameter Value EGRAN 4 0x10 BETAN 12 0 BETAP TQ AN1 7 03x10 AN2 7 03x10 gt BN1 1231x100 BN2 1 231x10 AP1 6 71x10 AP2 1 582x10 BP1 1 693x10 BP2 2 036x10 Silicon and Polysilicon Thermal Parameters The default values used for thermal conductivity and capacity are given in Table B 10 Table B 10 Effective Richardson Coefficients for Silicon and Poly Material TCA TCB TCC HCA HCB HCC HCD Silicon 0 03 1 56x107 1 65x10 1 97 3 6x1074 0 0 3 7x104 Poly 0 03 1 56x1073 1 65x10 1 97 3 6x1074 0 0 3 7x104 Silicon And Polysilicon Effective Richardson Coefficients B 8 SILVACO International Material Systems Table B 11 Effective Richardson Coefficients for Silicon and Poly Material ARICHN A cm2 K ARICHP A cm2 K2 Silicon 110 0 30 0 Poly 110 0 30 0 SILVACO Inte
17. x applies to the Ge component SiGe is then specified as Si _ Ger an exception to rule 4 e AlGaAs This is specified as Al Gay_ As This is an exception to rule 2 InGaAsP The convention N 1_ Ga jASvy P z y as set forth by Adachi is used This is an exception to rule 4 SILVACO International B 5 ATLAS User s Manual Volume 2 Silicon and Polysilicon The material parameters defaults for Polysilicon are identical to those for Silicon The following paragraphs describe some of the material parameter defaults for Silicon and Polysilicon Note Within the Physics section of this manual a complete description is given of each model The parameter defaults listed in Chapter Three are all Silicon material defaults Silicon and Polysilicon Band Parameters Table B 2 Band parameters for Silicon and Poly Material Fes a B Nc300 Nv300 x eV per cc per cc eV Silicon 1 08 4 73x1074 636 0 2 8x101 1 04x101 17 Rony 108 4 73x1074 636 0 2 8x10 9 1 04x10 9 4 17 Silicon and Polysilicon Dielectric Properties Table B 3 Static dielectric constants for Silicon and Poly Material Dielectric Constant Silicon 11 8 Poly 11 8 Silicon and Polysilicon Default Mobility Parameters The default mobility parameters for Silicon and Poly are identical in all cases The defaults used depend on the particular mobility models in question A full description of each mobility
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