SIMTarget user's guide
Contents
1. From To Width of layers 1E15 at cm M 4 gt HN Target description Target simulation Concentrations Curves Results Elements 4 Isotopes Aloys lt Ready Figure 6 Specification of deposited layers composition diffusion process substrate composition dopant and way of slicing the sample 13 3 3 Generation of the SIMNRA target file The sample described in section 3 2 1 is used here in order to show how the routine generates the target file At the end of the target description the layout of all SIMTarget sheets is updated and the Target simulation sheet is ready to generate the target file Tables showing the Gaussian Lorentzian and Boltzmann parameters all initialised to 0 are presented in this sheet Set the desired values for these parameters and press the Create SIMNRA target button Figure 7 E Microsoft Excel SIMTarget 1 0 xls ea File Edit View Insert Format Tools Data Window Help Type a question for help F X Lil J I K L M N J L Colaux PMR University of Namur FUNDP Depth profile of Test Curve Full width at Half Maximum ES at cm Amplitude Center at x 1E15 at em Full width at Lorents EIE m Half Maximum Ge t m Ets at cm Area of Curve ES at cm Element ee 13C Gauze 43 Concentration o 3 8 0 300 4 Element sas 5000 6000 Retain2. 2 x In 22 The offset yo amplitude A centre Xo and Full Width at Half Maximum W7 are the Gaussian parameters determined by the user in the SIMTarget code Concentration a u 0 200 400 600 800 Depth a u Figure 14 Representation of the Gaussian function used by SIMTarget for yo 5 A 90 and W 200 4 3 Lorentzian function The Lorentzian function can be used to model the presence of dopant inside the sample The concentration of the dopant y calculated at the depth X is given in by AW 4X XY W Y where yo W A and Xo are the offset the Full Width at Half Maximum the amplitude and the centre of the Lorentzian curve respectively Figure 15 23 The offset yo amplitude A centre Xo and Full Width at Half Maximum W are the Lorentzian parameters determined by the user in the SIMTarget code Concentration a u 0 200 400 600 800 1000 Depth a u Figure 15 Representation of the Lorentzian function used by for y 5 A 90 and W 150 24 5 Examples Three different applications are presented in order to illustrate the power of the combination of SIMTarget and SIMNRA programs to characterise complex samples by ion beam analysis Nuclear Reaction Analysis NRA of co implantation of carbon and nitrogen into copper Non Rutherford Backscattering Spectroscopy NBS of a metallic oxide deposited by physical vapour deposition PVD at high temperatu
3. for copper simultaneously implanted with 13C and 14N at room temperature The SIMNRA target composition was adjusted using the SIMTarget code in order to obtain the best agreement between the experimental and the simulated spectra Figure 16 This result was achieved using a thick sample of pure copper A layer of contamination of 265 x 10 at cm thick was added to take into account the carbon build up occurring during the implantation process A Boltzmann distribution was applied at the interface between carbon contamination and copper in order to model the ion beam mixing with the implantation beam Eight Gaussian curves were used to model the different carbon and nitrogen ion species differing charge states co implanted into the copper As the target composition varies very quickly at the interface the first 1000 x 10 at cm of the sample were sliced into thin 50 x 10 at cm layers The rest of the sample was sliced into layers of 125 x 10 at cm The depth profile generated in less than 10 seconds by the SIMTarget code running on a Pentium 1 60 GHz 512 Mb of RAM is presented in Figure 17 Thanks to the very good depth resolution of the d a nuclear reactions the shape of these depth distributions can directly be observed in the peaks showed in the insets of Figure 16 The carbon and nitrogen depth distributions are shown in more details in Figure 18 As labelled on the figure each Gaussian curve can be associated with
4. Energy MeV Figure 22 Simulated curves calculated by SIMNRA for the FeN Fe O bi layers deposited onto a carbon substrate analysed by RBS with an a beam of 1 50 MeV 31 6 Acknowledgements We would like to warmly thank A Lafort from the Laboratory of Structural Inorganic Chemistry Chemistry Department University of Li ge for making the metallic oxide deposited material and J Demarche from the LARN for performing the analysis of this sample and for agreeing to be the Beta Tester of SIMTarget program We give also our thanks to Dr M Mayer for offering to put a link for the SIMTarget code on the SIMNRA website 32 1 2 3 4 5 6 7 References N P Barradas et al Nucl Instr Meth B 266 2008 1338 L Mayer SIMNRA a Simultaiton Program for the Analysis of NRA RBS and ERDA Proc 15th Int Conf Appl Accelerators in Research and Industry J L Duggan and I L Morgan eds AIP Conf Proc 475 1999 541 J L Colaux G Terwagne Nucl Instr Meth B Submitted 2009 M Kokkoris P Misaelides S Kossionides C Zarkadas A Lagoyannis R Vlastou C T Papadopoulos A Kontos Nucl Instr Meth B 249 2006 77 S Pellegrino L Beck P Trouslard Nucl Instr Meth B 219 20 2004 140 J L Colaux T Thome G Terwagne Nucl Instr Meth B 254 2007 25 33
5. of target file gt My Recent Documents My Documents My Connie My Network Places Cancel es A M 4 gt Target description Target simulation Concentrations Curves Results Elements 4 Isotopes Aloys Out lt Ready Figure 2 SIMNRA target file information 3 2 1 Thick samples Insert details of the thickness and the number of elements of the contamination layer Specify the nature of each element by writing its chemical symbol with the keyboard A dialog box will warn you if the element or the isotope chosen is not available in the SIMNRA code Alloys can also be used if they have previously been defined in the Alloys sheet see section 3 5 2 If the surface contamination contains several elements the concentration of the last constituent will be automatically determined by the program If no contamination layer is required set the thickness and the number of elements to 0 When all grey cells are completed press the Confirm button Bookman Old Style 8 Fo gt M v x ah L a Which sample Thick or Multilayer Multilayer Confirm Reset Import Target description Change folder to generate Target file Version of SIMNRA program 604 Path to write the SIMNRA target file iC TEMP Name of target file Fer ayer of contamination Thickness of this Layer 1E15 at cw 50 Number of elements ss i Which elements a
6. of the sample The sample is then sliced as describe in the Target description sheet see section 3 2 and a very simple algorithm determines the mean composition of each sample slice The results are then plotted in SIMTarget and written in the SIMNRA target file More details about the algorithm used by SIMTarget can be found in reference 3 In order to understand the meanings of the different curve parameters used in SIMTarget code a very short description of the Boltzmann Gaussian and Lorentzian functions is presented below 4 1 Boltzmann function The Boltzmann distribution is used to carry out the transition between two layers in order to model the diffusion process Let us consider an element of which the concentration is A in the Layer 1 and A in the Layer 2 If Xo is the depth position of the interface between these two layers the concentration of the element at the depth X is given by A A PR rame l e where dx is related to the width W of the Boltzmann distribution Figure 12 by W dx 2 x In 0 9 a 0 9 The width of the Boltzmann distribution W is the parameter determined by the user in the SIMTarget code 20 100 80 3 J 60 S a E 40 o Q S O 20 0 200 400 600 800 1000 Depth a u Figure 12 Representation of the Boltzmann function used by SIMTarget to model the diffusion process for A 0 Az 100 and W 300 Note that the use of Boltzmann distribution ca
7. sample composition was adjusted using the SIMTarget program A metallic oxide layer of 1800 x 10 at cm on a stainless steel substrate was used The stainless steel diffusion indicated by the small signal rising up at 2 25 MeV in Figure 19 was modelled by adding 2 6 atomic percent of stainless steel inside the deposited layer and by applying a Boltzmann profile at the interface The diffusion can clearly be observed on the simulated elemental spectra shown in thin colour lines in Figure 19 A Lorentzian distribution of oxygen 28 centred on 1900 x 10 at cm was added in order to model the substrate oxidation occurring prior to the deposition process The target depth profile sliced into layers of 70 x 10 at cm is shown in Figure 20 Its generation took less than 5 seconds with the SIMTarget code running on a Pentium 1 60 GHz 512 Mb of RAM Note that the transition between deposited layer and substrate does not look like a Boltzmann distribution due to the presence of the Lorentzian distribution 3 1 0 _ Stainless Steel 081 Oxygen 4 Metallic element 0 6 0 4 Atomic concentration 0 2 Depth 10 at cm Figure 20 Depth distributions of stainless steel SS metallic element M and oxygen O generated by SIMTarget code in order to perform the SIMNRA simulation presented in Figure 19 29 5 3 RBS of multilayer coatings deposited on carbon SIMTarget and SIMNRA codes can be also
8. 1 0 xls is composed of eleven Excel spreadsheets A short description of each is given below gt Target description gt Target simulation gt Concentrations gt Curves gt Results gt Elements gt Isotopes This interactive sheet allows the user to describe the target material step by step as detail in the section 3 2 Contains the information about any dopant present i e parameters of Gaussian or Lorentzian curves and diffusion process i e width of Boltzmann distribution The general graph showing the depth profile of each element of the target is also included on this sheet Modify or copy this graph requires to unprotect the Target simulation sheet Deleting this graph may cause errors in the operation of SIMTarget Allows determination of the mean concentration of any dopant between depths x and x2 chosen by the user Contains the depth profile of each Gaussian or Lorentzian curve for any dopants present This sheet is completed automatically by SIMTarget giving the depth profile of each target element Contains information about all the elements available in SIMNRA code As this is used to generate the SIMNRA target file the contents of this sheet can not be modified under any circumstances Contains information about all isotopes available in SIMNRA code As this is used to generate the SIMNRA target file the contents of this sheet can not be modified under any circums
9. How many deposited layers in a stack ni How many stack M 4 gt MN Target description Target simulation Concentrations Curves Results Elements Isotopes Alloys 4 lt Ready Figure 5 Description of the contamination layer and specification of the multilayer structure 11 Define the composition of deposited layers as described above for the layer of contamination for as many layers as necessary Figure 6 SIMTarget code is able to model the diffusion process using a Boltzmann distribution to carry out the transition between two layers see section 4 1 For each interface select Boltzmann in the item list if you wish to model a diffusion process Otherwise select None Parameters of the Boltzmann function will be set in the Target simulation sheet Define the substrate composition as described above for the layer of contamination Gaussian and Lorentzian functions are available to simulate the presence of dopants inside the target see sections 4 2 and 4 3 Specify the number of dopants desired For each one specify the chemical symbol the type of curve and the number of curves required Parameters of these curves will be defined in the Target simulation sheet If no dopant is required set the number of dopants to 0 The last step consists of determining the way of slicing the sample in order to generate the SIMNRA target file It is possible to define different sections which can be sliced
10. SIM Target 1 0 User s guide J L Colaux University of Namur 61 rue de Bruxelles 5000 Namur Belgium E mail julien colaux fundp ac be Phone 32 81 725479 Fax 32 81 72 54 74 1 Introduction _ 2 Installation __ 3 Using SIMTarget 3 1 Overview of SIMTarget 3 2 Describing a target 3217 Thick samples tu scsccssdsiepstssseuienserevionucccstesevve ches teverngutetcocbetgusesescorsasentveostets 3 22 Multilayer samples cant nent terne inside 3 3 Generation of the SIMNRA target file 3 4 Export Import of the target description 3 5 Extra tools 3 5 1 ConCenttations sheet 44 tant anne transit esta a adeuesacadtesSeieesios 3 35 27 Alloys Sheet resserre a aE fente 4 Computational approach 4 1 Boltzmann function 4 2 Gaussian function 4 3 Lorentzian function 5 Examples 5 1 NRA of co implantation of carbon and nitrogen into copper 5 2 NBS of metallic oxides deposited on stainless steel 5 3 RBS of multilayer coatings deposited on carbon 6 Acknowledgements 7 References 22 23 25 25 28 30 32 33 1 Introduction Ion beam analysis techniques are often used for the determination of elemental concentration depth profiles of various samples The final results rely on simulations fitting and calculations made by dedicated codes written for specific techniques 1 Amongst the different softwares available SIMNRA 2 is one of the more powerful code
11. an implanted ion species 26 Atomic concentration Atomic concentration Depth 10 at cm Figure 17 Depth distributions of Cu C surface contamination C and N generated by SIMTarget code in order to perform the SIMNRA simulation presented in Figure 16 0 15 0 10 0 05 0 00 0 2 0 1 Depth 10 at cm Figure 18 Depth profiles of C and N generated by the SIMTarget code for the copper sample simultaneously implanted with C and N at room temperature 27 5 2 NBS of metallic oxides deposited on stainless steel Metallic oxide thin film was deposited using reactive DC magnetron sputtering onto polished stainless steel substrate at high temperature about 400 C The thickness of the deposited layer was estimated at 200 nm The sample was characterised by Non Rutherford Backscattering Spectroscopy using a He beam of 3 0 MeV A typical experimental spectrum recorded at 165 is presented in the Figure 19 Signals from oxygen O stainless steel SS and metallic element M are indicated by arrows on the figure The simulated curve was calculated by SIMNRA 6 04 code Acquisition time 45 min Integrated charge 35 uC Solid angle 4 msr 1500 3 3 1000 se 500 0 0 5 1 0 1 5 2 0 Energy MeV Figure 19 Experimental red line and simulated blue line NBS spectra recorded at 165 for the metallic oxide deposited onto stainless steel at high temperature The
12. ed doze LIENS at cm o 1000 2000 3000 Depth 10E15 aticm 4000 Boltzmann Diffusion Between 3_ _and Substrate width ENS at em Recall curves parameters of last simulation Exnort Target descrintion ral 4 gt n Target description Target simulation 13C 15N Concentrations Curves Results Elements Isotopes Alloys lt gt Ready NUM Figure 7 Example of SIMNRA target generation When the Create SIMNRA target button is pressed the depth distribution of each target element is calculated and the results are presented in a graph in the Simulation target sheet In this graph the depth profile of each dopant is obtained to sum the contribution of each Gaussian and Lorentzian curve These curves are plotted in the sheets named after the different dopants in order to visualise their influence on the target composition Figure 8 14 The retained dose expressed in 10 at cm is calculated for each dopant and presented in a table below the graph Figure 7 The integral of each Gaussian and Lorentzian curve can also be found in a table shown at the right of this general graph Finally the SIMNRA target file is generated in the path filename specified in Target description sheet El Microsoft Excl SiMTarget 1 0 x Ee fcrosoft Excel SIMTareet 1 0 x15 He J L Colaux PMR University of Namur FUNDP J L Colaux PMR University of Nam
13. elements Qu Which elements y Atomic concentration 2 s0 20 Diffusion between Layer of cont and Substrate Substrate s specifications Number of elements or a Atomic concentration ae E Number of elements _ Type of stitution Gauss Gus Low Number of curve for each element i i an Poe 32 Sana gers speotcatons Number of sections in the SIMNRAtarget 2 Sectiont Section2 0 From To Width of layers 1E15 atom Il 4 4 n Target description Target simulation Concentrations Curves Results Elements Isotopes Allo lt Ready Figure 4 Specifying the diffusion process substrate composition dopant and method of slicing the sample When the target description is completed press the Write tables and graphs button This saves the target description in the Output parameters sheet and the page layout of all sheets is updated A new sheet is also created for each dopant in order to show the depth distribution of each Gaussian and Lorentzian curve which is very convenient for adjusting the parameters of these curves during the target simulation Finally the Simulation target sheet is activated and ready to generate the SIMNRA target file 10 3 2 2 Multilayer samples Insert the thickness and the number of element of the layer of contamination Figure 5 Specify the nature of each element by
14. ins dopants it may be interesting to determine their average concentration in a specific range The Concentration sheet allows users to calculate this average concentration between depths x and x as set by the user in a text box Figure 10 The retained dose of each dopant is also determined by the program in the same range Figure 10 presents the results obtained for the sample described in the section 3 2 1 for a range covering all the sample left or centred around the maxima of C and N depth distributions right Note that the retained doses calculated in the first case left part of Figure 10 are equal to the retained doses displayed on the Target simulation sheet Figure 7 E Microsoft Excel SIMTarget 1 0 xls MER E microsoft Excel SIMTarget 1 0 xts B c B Depth 10E15 at cm Depth 10E15 at cm from from o 500 Calculate Calculate implanted element Mean concentration Retained Dose implanted element Mean concentration Retained Dose n P SE at 1E15 at em n P m at 1E15 at em 13C 9 49 474 6 16 30 407 5 15N 7 24 361 9 12 82 320 6 il N 13 m 4 oi Target description Target simulation 13C 15N Concentrations G m 4 mN Target description Target simulation 13C 15N Concentrations G Ready Ready Figure 10 Mean concentration and retained dose calculated for sample described in the section 3 2 1 and for two differe
15. into different thicknesses Therefore very thin slices can be chosen where the sample composition changes significantly i e around the interface between two layers and thicker slices can be used everywhere else Note that if the thickness of the contamination layer is not divisible by the thickness chosen to slice the sample SIMTarget adapts the thickness of the last slice automatically in order to preserve the specified thickness of the contamination layer For example if a layer of contamination of 160 x 10 at cm has to be sliced in slices of 30 x 10 at cm the layer will be sliced into four slices of 30 x 10 at cm and one of 40 x 10 atcm Note also that the SIMNRA program does not accept a target file containing more than 102 layers A dialog box will warn you if this number is exceeded In this case the target file is not generated and the requested method of slicing the sample has to be adapted in order to reduce the number of slices When the target description is completed press the Write tables and graphs button This saves the target description in the Output parameters sheet and the page layout of all sheets is updated A new sheet is also created for each dopant in order to show the depth distribution of each Gaussian and Lorentzian curve which is very convenient for adjusting the parameters of these curves during the target simulation Finally the Simulation target sheet is activated and ready
16. ion sheet i e Thickness of different layers Atomic concentration of elements methods to slice the sample These parameters appear in grey cells in the Target description sheet The unavailable parameters i e Nature of elements Number of dopants appear in red cells If a modification of these unavailable parameters is required the program has to be reset by clicking the Reset button on the Target description sheet In this case the Recall last parameters button can be very useful to avoid having to re enter all the target description data manually The parameters of 15 Boltzmann Gaussian and Lorentzian curves can also be recalled using the Recall curves parameters of last simulation button in the Target simulation sheet 16 3 4 Export Import of the target description As mentioned in the previous section the Recall last parameters and Recall curves parameters of last simulation buttons are very useful to avoid having to re enter all the target description data manually when the target description has to be reset However these buttons can only recall the parameters of the last target generated by the SIMTarget code Due to this limitation a function to export the complete target description in order to recall it later has been provided When the agreement between the experimental spectrum and the curve simulated by SIMNRA is considered to be sufficient hit the Expor
17. late all other samples Move the mouse over the box at the right of cell A1 and tick the desired type of sample Figure 1 Ex Import Target description Set tolde erat 1 fell Bel 4 5 6 7 8 M 4 gt W Target description Target simulation Concentrations Curves Results Elements Isotopes Alloys f O lt Ready Figure 1 Type of sample selection Information about the SIMNRA target file will appear when hitting the Next button Figure 2 Version 6 04 of the SIMNRA program is automatically selected and a dialog box simulating Windows Explorer is opened in order to select the folder in which the target file will be created If another version of SIMNRA is used select this within the item list of cell B5 Specify the name of the target file and click the Next button again The following options appearing on the screen are specific for Thick samples or Multilayer samples and are described in the sections 3 2 1 and 3 2 2 respectively Note that the SIMNRA version directory and name of the target file will be saved when the target description is completed and automatically recalled during the future uses of SIMTarget code rosoft Excel SIMTarget 1 0 R 2 ae O Thick Which sample Thick or Multilayer O Multilayer Import Target description Looki TEMP o lQ Xa A Toos Version of SIMNRA program co F Path to write the SIMNRA target file gt ses Name
18. mp DSC UE G3 Atomic concentration A BO o 14 4 gt WN Target description Target simulation Concentrations Curves Results Elements Isotopes f Aloys f Out lt Ready Figure 3 Specification of surface contamination layer The SIMTarget code is able to model the diffusion process using a Boltzmann distribution to simulate the transition between two layers see section 4 1 Select Boltzmann in the item list if you wish to model a diffusion process between the surface contamination and the substrate Figure 4 Otherwise choose None This option will not appear if no layer of contamination has been defined in the previous step Parameters of the Boltzmann function will be set in the Target simulation sheet Define the substrate composition as depicted above for the surface contamination Gaussian and Lorentzian functions are available to simulate the presence of dopant inside the target see sections 4 2 and 4 3 Specify the number of dopants desired For each set the chemical symbol the type of curve and the number of curves required Parameters of these curves will be defined in the Target simulation sheet If no dopant is required set the number of dopants to 0 The last step consists of determining the way of slicing the sample in order to generate the SIMNRA target file It is possible to define different sections which can be sliced into different thicknesses Therefore very thin
19. n lead to a target composition having no physical interpretation This is the case when the half width of Boltzmann distribution is larger than the thickness of one of the two layers implicated in the diffusion process In order to understand this phenomenon let us consider a layer of 200 x 10 at cm of pure carbon deposited on a copper substrate If a Boltzmann distribution with a width of 500 x 10 at cm is applied to the interface we obtain the depth profile of carbon presented in blue in the Figure 13 On this figure we can clearly observe that the number of carbon atoms having diffused into copper red surface labelled Az is more important than the number of carbon atoms having left the deposited layer green surface labelled A That means that the integral of the carbon depth profile equal to 216 x 10 at cm is greater than the total amount of carbon initially specified 200 x 10 at cm 21 Concentration gt Dm _ 0 200 400 600 800 1000 Depth 10 at cm Figure 13 Artefact of the use of Boltzmann distribution 4 2 Gaussian function The Gaussian function can be used to model the presence of dopant inside the sample The concentration of the dopant y calculated at the depth X is given by y y Ae where yo A and Xo are the offset the amplitude and the centre of the Gaussian curve respectively Figure 14 Wis related to the Full Width at Half Maximum W of the Gaussian distribution by 2 W
20. nt ranges 3 5 2 Alloys sheet This interactive sheet allows users to define different alloys which will be assumed by the SIMTarget code to be treated as a single element This alloy will be replaced in the SIMNRA target file by its constituent elements taking into account the concentration specified in the Alloys sheet during the SIMNRA target file generation This option is 18 particularly interesting when the user wishes to adjust the concentration of an alloy in a deposited layer see example in section 5 2 Choose a symbol in order to define a new alloy A dialog box will warn you if the symbol chosen is already used in the Elements Isotopes or Alloys sheets In this case you have to change the symbol Give the number of elements contained in the alloy According to this number new grey cells will appear allowing you to define the nature and the concentration of each element All elements and isotopes available in the SIMNRA code can be used The concentration of the last constituent element is automatically determined by the program Type a question for help f X A B 1 Symbol Number of elements 2 E Ready Figure 11 Definition of the stainless steel composition 19 4 Computational approach The SIMRA target file is generated when the sample structure has been comprehensively defined For this purpose the code determines the analytical depth profile of each element
21. re and Rutherford Backscattering Spectroscopy of a multilayer coatings deposited by PVD on a silicon substrate The aim of this section is to give an overview of the potential of the SIMTarget code Thus we simply present the way in which SIMTArget was used to obtain these results More details about the production of samples and the techniques of analysis can nevertheless be found in a previous work 3 5 1 NRA of co implantation of carbon and nitrogen into copper These samples are polished polycrystalline copper substrates simultaneously implanted with BC and N using a non deflected beam line of a 2MV ALTAIS Tandetron accelerator Figure 16 shows a typical experimental spectrum recorded at 150 by NRA with a 1 05 MeV incident deuteron beam The nuclear reactions responsible of the different peaks are indicated on the figure The simulation was performed with the SIMNRA 6 04 program using nuclear reaction cross sections measured by M Kokkoris et al 4 S Pellegrino et al 5 and J L Colaux et al 6 Acc l rateur Lin aire Tandetron pour I Analyse et l Implantation des Solides 25 Acquisition time 30 min Integrated charge 45 uC Solid angle 2 msr 220 200 180 160 140 C d p C 60 C d 0 B Yield a u gt e Da oo N O 20 FNG a C Energy MeV Figure 16 Experimental red line and simulated blue line NRA spectra recorded at 150
22. s used to simulate experimental spectra obtained by Rutherford Backscattering Spectroscopy RBS Elastic Recoil Detection Analysis ERDA Nuclear Reaction Analysis NRA or Medium Energy Ion Scattering MEIS The best agreement between the theoretical and experimental results is obtained by adjusting the composition of the SIMNRA target file When the structure of the sample under analysis becomes more complicated the target file has to be manually sliced into several layers which can rapidly become tedious SIMTarget code has then been designed in order to easily generate all SIMNRA target files regardless to the sample complexity It is able to model the diffusion between two layers as well as the presence of dopants within the sample A graphical display shows the depth distribution of each element which is very useful to adjust the target composition during simulations 2 Installation SIMTarget code has been written in Visual Basic for Application VBA within Microsoft Excel 2003 The execution of the SIMTarget macros has to be enabled in Excel in order to run this program To do this select Tools menu point Macro click Security and then choose the Medium level of security At this level a dialog box will ask if you want to enable the macros when opening the SIMTarget 1 0 xls file Select Enable macros and then SIMTarget is ready for use 3 Using SIMTarget 3 1 Overview of SIMTarget SIMTarget
23. slices can be chosen where the sample composition changes significantly i e around the interface between two layers and thicker slices can be used everywhere else Figure 4 Note that if the thickness of the contamination layer is not divisible by the thickness chosen to slice the sample SIMTarget adapts the thickness of the last slice automatically in order to preserve the specified thickness of the contamination layer For example if a layer of contamination of 160 x 10 at cm has to be sliced in slices of 30 x 10 at cm the layer will be sliced into four slices of 30 x 10 at cm and one of 40 x 10 at cm Note also that the SIMNRA program does not accept a target file containing more than 102 layers A dialog box will warn you if this number is exceeded In this case the target file is not generated and the requested method of slicing the sample has to be adapted in order to reduce the number of slices E Microsoft Excel SIMTarget 1 0 xls EX A Sle Edt view Insert rom Tools Data Window Help Type a question for help m Bt X Bookman Old Style x 8 El R 5 IL fo Thick Thick Which sample Thick or Multilayer slayer Write tables and graphs 3 Import Target description Change folder to generate Target file te Version of SIMNRA program et Path to write the SIMNFA target file CATEMP Name of target file jer of contamination i Thickness of this Layer 1E15 atem S0 O Number of
24. t Target description button in the Target simulation sheet The complete description of the target is then written in a text file typical size 20kb The name and the directory of this file are identical to that chosen for the SIMNRA target file In order to import a target description reset the SIMTarget program by hitting the Reset button in the Target description sheet Then click the Import Target description button A dialog box simulating Windows Explorer is opened in order to select the file to import Figure 9 Select the required text file and click open The target description is then automatically loaded into the program All curves and diffusion parameters are automatically recalled and the Target simulation sheet is activated and ready to generate a target file A dialog box will also prompt you to change the name or the directory of the target file in order to avoid overwriting the existing files Microsoft Excel SIMTarget 1 0 x1s Insert Format Tools Data Window Help ol ah Documents Desktop My Documents My Computer File name My Network Places Files oF type Text Files txt x EJ lt gt MN Target description Target simulation Concentrations Curves Results Elements Isotopes 4 amp lt Ready Figure 9 Import a target description file 17 3 5 Extra tools 3 5 1 Concentrations sheet When the sample conta
25. tances gt Alloys This interactive sheet allows the user to define any alloys that you wish to use in the target description see section 3 5 2 gt Output parameters Contains all the information required to reset the program or to recall parameters of a previous simulation The contents of this sheet can not be modified under any circumstances gt Target Format Contains information about the format of the SIMNRA target file The contents of this sheet can not be modified under any circumstances gt Graphl If any dopants are used in the target description this graph is duplicated in order to present the depth profile of each Gaussian or Lorentzian curve It must never be deleted Many of these sheets are protected in order to avoid any involuntary modification of contents Unprotecting and modifying these sheets may cause errors in the operation of SIMTarget Changing the names of the sheets can also cause errors 3 2 Describing a target The target description is entirely performed within the interactive Target description sheet The contents of this sheet will be automatically updated after each describing step Basically users must insert data to complete the cells appearing in grey before continuing to the next step First of all Thick or Multilayer sample has to be selected Thick sample is specifically used to model ion implantation into a substrate while Multilayer sample is used to simu
26. to generate the SIMNRA target file 12 E Microsoft Excel SIMTarget 1 0 xls DAR 55 pie Edit View Insert Format Tools Data Window Help Type a question for help 8 X g RENFE PI 2 i LE a 7 1 Ci A l Bookman Old Style x8 x B Z U aq TORA C12 d fH an D E E G H Fr Which sample Thick or Multilayer fo Multilayer Write tables and graphs Recall last parameters Reset Import Target description Change folder to generate Target file w Blu ro gt v Version of SIMNRA program Path to write the SIMNRA ts file Name of tarzet file n wer of contamination Thickness of this Layer 1E15 at cm Number of elements Which elements 5 Atomic concentration 85 5 aa i if On O1 09 How many deposited lay in a stack How many stack N o 4 Thickness of this Layer 1E15 at cm Number of elements Which elements Atomic concentration Thickness of this Layer 1E15 at cm Number of elements Which elements Atomic concentration Diffusion between Layer 2 and Next Layer Diffusion between Last Layer and Substrate Substrate s specifications Number of elements Which elements Atomic concentration Dopant Number of elements Which elements Type of distribution Number of curve for each element SIMNRA layer s specifications Number of sections in the SIMNRA target
27. ur FUNDP Depth profile of 13C Depth profile of 15N 18N Gauss 1 8 15N Gauss 2 15N Gauss 3 SN Gauss 4 Total of 15N 13C Gauss 1 180 Gauss 2 y 13C Lorentz 1 Total of 13C Concentration 1000 2000 3000 4000 8000 6000 3000 4000 5000 6000 Depth 10E15 atom Depth 10E15 atiom e a y MN Taget dscipton Target smuaton xae TSN Z Concentrators Curves Rests Elements Z 5O lt 3 e gt WK Target description Z Target simulation 2130 15n Concentrations Z Curves Z Results Elements Tea Figure 8 Depth profiles of C and N showing the contribution of each Gaussian and Lorentzian curves The target file is directly readable in SIMNRA code in order to simulate the experimental spectrum under analysis According to the quality of this simulation users can adapt the target parameters in SIMTarget code pressing the Create SIMNRA target button each time to re write the code The depth profile of each element is computed again and the SIMNRA target file is overwritten with the new target composition Load this file in the SIMNRA program and run it again Several iterations between SIMTarget and SIMNRA codes may be necessary to obtain good agreement between the experimental and simulated spectra Note that in addition to the parameters shown in the Target simulation sheet some parameters remain adjustable in the Target descript
28. used to determine the best experimental setup allowing characterisation of more complex samples such as a stacked multilayer We present here the case of five FeN Fe2O3 bi layers deposited onto carbon 1 0 0 8 E 06 S es js Ann S 044 2 a l l y D AAA 0 0 0 1 2 3 4 5 Depth 10 at cm Figure 21 Depth distributions of carbon iron nitrogen and oxygen generated by SIMTarget to model the Fe 0 FeN bi layers deposited by reactive magnetron sputtering onto a carbon substrate The thickness of FeN and FeO layers was fixed at 450 x 10 at cm and the transition of each interface was carried out using a Boltzmann distribution with a width of 200 x 10 at cm The sample was sliced into layers of 70 x 10 at cm The target depth profile was generated in less than 5 seconds with a Pentium 1 60 GHz 512 Mb of RAM and is presented in the Figure 21 The simulated curve obtained for a He beam of 1 50 MeV hitting the sample at an angle of 30 with respect to the normal of the surface and a detection angle of 165 is presented in Figure 22 We can observe that the signal of iron is well isolated The particles 30 backscattered by the oxygen atoms of the two first bi layers are also well separated from the rest of the spectrum This experimental setup should then allow us to characterise the two first bi layers 15000 _ 10000 5 2 gt 5000 0 0 0 2 0 4 0 6 0 8 1 0 1 2
29. writing its chemical symbol with the keyboard A dialog box will warn you if the element or the isotope chosen is not available in the SIMNRA code Alloys can also be used if they have previously been defined in the Alloys sheet see section 3 5 2 If the surface contamination contains several elements the concentration of the last constituent will be automatically determined by the program If no layer of contamination is required set the thickness and the number of elements to 0 Set the number of deposited layers and the number of stacked multilayers The number of stack allows to repeat several times the deposited layers in order to model the stacking of multilayers on a substrate see example in section 5 3 A single coating is then achieved by choosing only one deposited layer in a single stack see example in section 5 2 When the description of layer of contamination and structure of deposited layers is completed press the Confirm button EJ Microsoft Excel SIMTarget 1 0 xls DAR a File Edit View Insert Format Tools Data Window Help Type a question for help SES An MENT RENAN RO RS IE RE 2 Confirm Recall last parameters Rest Import Target desoription Change folder to generate Target file Version of SIMNRA prozram Path to write the SIMNRA target file Name of target file 10 Thickness of this Layer 1E15 at cm 11 Number of elements Which elements Atomic concentration
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