Pub Date : 1996-01-01DOI: 10.1109/TCAD.1996.6449168
M. Ancona, Z. Yu, W. Lee, R. Dutton, P. V. Voorde
The density-gradient approach to quantum transport theory is used to model the inversion layer profiles, threshold voltages and C-V characteristics of MOS capacitors with ultra-thin oxides and polysilicon gates. The results (without fitting parameters) are found to compare quite well with experimental data and with calculations made using quantum mechanics. Comparisons are also made with results obtained using previous phenomenological methods and these favor density-gradient theory as well, especially in its being physically meaningful and predictive. Overall, the results of this work show that density-gradient theory provides a physics-based approach to device modeling problems in which quantum confinement effects are significant that is simple enough for engineering applications.
{"title":"Simulation of quantum confinement effects in ultra-thin-oxide MOS structures","authors":"M. Ancona, Z. Yu, W. Lee, R. Dutton, P. V. Voorde","doi":"10.1109/TCAD.1996.6449168","DOIUrl":"https://doi.org/10.1109/TCAD.1996.6449168","url":null,"abstract":"The density-gradient approach to quantum transport theory is used to model the inversion layer profiles, threshold voltages and C-V characteristics of MOS capacitors with ultra-thin oxides and polysilicon gates. The results (without fitting parameters) are found to compare quite well with experimental data and with calculations made using quantum mechanics. Comparisons are also made with results obtained using previous phenomenological methods and these favor density-gradient theory as well, especially in its being physically meaningful and predictive. Overall, the results of this work show that density-gradient theory provides a physics-based approach to device modeling problems in which quantum confinement effects are significant that is simple enough for engineering applications.","PeriodicalId":100835,"journal":{"name":"Journal of Technology Computer Aided Design TCAD","volume":"52 1","pages":"1-17"},"PeriodicalIF":0.0,"publicationDate":"1996-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"90550189","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1996-01-01DOI: 10.1109/TCAD.1996.6449166
D. Adalsteinsson, J. Sethian
Level set techniques are numerical techniques for tracking moving interfaces, and have been applied to a wide collection of problems in front propagating and surface advancement. The techniques are robust, accurate, unbreakable, and extremely fast, and can be applied to highly complex two and three dimensional surface topography evolutions in etching, deposition, and photolithography, including sensitive flux/visibility integration laws, simultaneous etching and deposition, effects of non-convex sputter laws demonstrating faceting, as well as ion-sputtered re-deposition and re-emission with low sticking coefficients, and surface diffusion.
{"title":"Level set methods for etching, deposition and photolithography development","authors":"D. Adalsteinsson, J. Sethian","doi":"10.1109/TCAD.1996.6449166","DOIUrl":"https://doi.org/10.1109/TCAD.1996.6449166","url":null,"abstract":"Level set techniques are numerical techniques for tracking moving interfaces, and have been applied to a wide collection of problems in front propagating and surface advancement. The techniques are robust, accurate, unbreakable, and extremely fast, and can be applied to highly complex two and three dimensional surface topography evolutions in etching, deposition, and photolithography, including sensitive flux/visibility integration laws, simultaneous etching and deposition, effects of non-convex sputter laws demonstrating faceting, as well as ion-sputtered re-deposition and re-emission with low sticking coefficients, and surface diffusion.","PeriodicalId":100835,"journal":{"name":"Journal of Technology Computer Aided Design TCAD","volume":"1 1","pages":"1-67"},"PeriodicalIF":0.0,"publicationDate":"1996-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"89701824","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1996-01-01DOI: 10.1109/TCAD.1996.6449163
H. Kirchauer, S. Selberherr
An overall three-dimensional photolithography simulator is presented, which has been developed for workstation based application. The simulator consists of three modules according to the fundamental processes of photolithography, namely imaging, exposure/bleaching and development. General illumination forms are taken into account. The nonlinear bleaching reaction of the photoresist is considered and electromagnetic light-scattering due to a nonplanar topography is treated by solving repeatedly the maxwell equations within an inhomogeneous medium. A novel extension of the two-dimensional differential method into the third dimension is presented and a numerically efficient implementation for exposure simulation under partial coherent illumination is described. the development process is simulated with a cellular based surface advancement algorithm.
{"title":"Three-dimensional photolithography simulation","authors":"H. Kirchauer, S. Selberherr","doi":"10.1109/TCAD.1996.6449163","DOIUrl":"https://doi.org/10.1109/TCAD.1996.6449163","url":null,"abstract":"An overall three-dimensional photolithography simulator is presented, which has been developed for workstation based application. The simulator consists of three modules according to the fundamental processes of photolithography, namely imaging, exposure/bleaching and development. General illumination forms are taken into account. The nonlinear bleaching reaction of the photoresist is considered and electromagnetic light-scattering due to a nonplanar topography is treated by solving repeatedly the maxwell equations within an inhomogeneous medium. A novel extension of the two-dimensional differential method into the third dimension is presented and a numerically efficient implementation for exposure simulation under partial coherent illumination is described. the development process is simulated with a cellular based surface advancement algorithm.","PeriodicalId":100835,"journal":{"name":"Journal of Technology Computer Aided Design TCAD","volume":"104 1","pages":"1-37"},"PeriodicalIF":0.0,"publicationDate":"1996-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"75953616","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1996-01-01DOI: 10.1109/TCAD.1996.6449164
C. Wasshuber, H. Kosina, S. Selberherr
A multipurpose single-electron device and circuit simulator is presented, with which it is possible to simulate a wide variety of single-electron devices. the simulator features among others the incorporation of co-tunneling by two different simulation methods, a graphical user interface and a graphical circuit editor. A new algorithm for the simulation of very rare events, where a Monte Carlo method is combined with a direct calculation, is outlined in detail.
{"title":"A single-electron device and circuit simulator with a new algorithm to incorporate co-tunneling","authors":"C. Wasshuber, H. Kosina, S. Selberherr","doi":"10.1109/TCAD.1996.6449164","DOIUrl":"https://doi.org/10.1109/TCAD.1996.6449164","url":null,"abstract":"A multipurpose single-electron device and circuit simulator is presented, with which it is possible to simulate a wide variety of single-electron devices. the simulator features among others the incorporation of co-tunneling by two different simulation methods, a graphical user interface and a graphical circuit editor. A new algorithm for the simulation of very rare events, where a Monte Carlo method is combined with a direct calculation, is outlined in detail.","PeriodicalId":100835,"journal":{"name":"Journal of Technology Computer Aided Design TCAD","volume":"8 1","pages":"1-18"},"PeriodicalIF":0.0,"publicationDate":"1996-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"90183368","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1996-01-01DOI: 10.1109/TCAD.1996.6449162
C. Pichler, R. Plasun, R. Strasser, S. Selberherr
With shrinking device dimensions and decreasing product-development cycles, fully-automated TCAD analysis of complete semiconductor processes and devices is becoming increasingly important. We present a programmable simulation environment for VLSI technology analysis, focusing on high-level tasks including response surface modeling (RSM) and optimization. Based on process and device simulation capabilities with heterogeneous simulation tools, split-lot experiments can be defined for fabrication process flows and simulation sequences. The parallel and distributed execution of independent split tree branches allow a fast computation of large-scale experiments. A persistent run data base keeps all simulation results and prevents unnecessary re-computations. Special emphasis has been put on establishing in an object-oriented fashion a uniform and easy-to-use interface for applications and extensions supplied by the user. the combination of a comfortable, intuitive visual user interface with the flexibility and versatility of a high-level programming language for TCAD applications results in a powerful tool for tcad integration, development, and production use.
{"title":"High-level TCAD task representation and automation","authors":"C. Pichler, R. Plasun, R. Strasser, S. Selberherr","doi":"10.1109/TCAD.1996.6449162","DOIUrl":"https://doi.org/10.1109/TCAD.1996.6449162","url":null,"abstract":"With shrinking device dimensions and decreasing product-development cycles, fully-automated TCAD analysis of complete semiconductor processes and devices is becoming increasingly important. We present a programmable simulation environment for VLSI technology analysis, focusing on high-level tasks including response surface modeling (RSM) and optimization. Based on process and device simulation capabilities with heterogeneous simulation tools, split-lot experiments can be defined for fabrication process flows and simulation sequences. The parallel and distributed execution of independent split tree branches allow a fast computation of large-scale experiments. A persistent run data base keeps all simulation results and prevents unnecessary re-computations. Special emphasis has been put on establishing in an object-oriented fashion a uniform and easy-to-use interface for applications and extensions supplied by the user. the combination of a comfortable, intuitive visual user interface with the flexibility and versatility of a high-level programming language for TCAD applications results in a powerful tool for tcad integration, development, and production use.","PeriodicalId":100835,"journal":{"name":"Journal of Technology Computer Aided Design TCAD","volume":"56 1","pages":"1-30"},"PeriodicalIF":0.0,"publicationDate":"1996-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"85239918","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1996-01-01DOI: 10.1109/TCAD.1996.6449177
W. Pyka, R. Martins, S. Selberherr
The reduction of computing time without loss of accuracy is a very important task for three-dimensional process simulation. We present new approaches for fast and stable simulation of etching and deposition processes by introducing non spherical structuring element algorithms to our morphological operation based cellular topography simulator. We demonstrate improvements and accelerations for a wide variety of etching and deposition models such as isotropic deposition, uni-directional etching, lithography development simulation, sputter deposition and reactive ion etching. we also draw comparisons with the originally implemented algorithm and other approaches such as the level set method. furthermore we show a fast, physically based, and accurate three-dimensional simulation of tin sputter deposition and, by means of a two metal layer interconnect structure, we demonstrate an efficient generation of three-dimensional geometries directly including layout information and photolithography simulation.
{"title":"Optimized algorithms for three-dimensional cellular topography simulation","authors":"W. Pyka, R. Martins, S. Selberherr","doi":"10.1109/TCAD.1996.6449177","DOIUrl":"https://doi.org/10.1109/TCAD.1996.6449177","url":null,"abstract":"The reduction of computing time without loss of accuracy is a very important task for three-dimensional process simulation. We present new approaches for fast and stable simulation of etching and deposition processes by introducing non spherical structuring element algorithms to our morphological operation based cellular topography simulator. We demonstrate improvements and accelerations for a wide variety of etching and deposition models such as isotropic deposition, uni-directional etching, lithography development simulation, sputter deposition and reactive ion etching. we also draw comparisons with the originally implemented algorithm and other approaches such as the level set method. furthermore we show a fast, physically based, and accurate three-dimensional simulation of tin sputter deposition and, by means of a two metal layer interconnect structure, we demonstrate an efficient generation of three-dimensional geometries directly including layout information and photolithography simulation.","PeriodicalId":100835,"journal":{"name":"Journal of Technology Computer Aided Design TCAD","volume":"5 1","pages":"1-39"},"PeriodicalIF":0.0,"publicationDate":"1996-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"86815000","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1996-01-01DOI: 10.1109/TCAD.1996.6449160
M. Fischetti, N. Sano, S. Laux, K. Natori
The empirical pseudopotential band-structure of Ge, Si, and GaAs is used to compute the impact ionization (pair production) rate for electrons and holes. The constant-matrix-element and Kane's random-k approximations are also employed, to assess the importance of the energy-dependence of the Coulomb matrix element, of momentum conservation, and of the joint density of states. For electrons in Si and electrons and holes in Ge and GaAs, the latter is found to be dominant, while for holes in Si momentum conservation appears to be an important constraint on ionization processes near threshold. These results are then fitted to an isotropie ionization rate, function of carrier energy only. Full-band-structure Monte Carlo simulations are finally performed in order to calibrate the acoustic and nonpolar-optical deformation potentials. The low-energy deformation potentials are obtained from the usual1 fits to experimental velocity-field characteristics, while high-energy deformation potentials are determined from fits to experimental data on the ionization coefficients. The usual ambiguity of conventional Monte Carlo calibration of the scattering parameters ∼ using both carrier-phonon and impact ionization rates as fitting entities ∼ is thus removed, giving us better confidence on the final result. The deformation potentials so obtained are in good agreement with those reported in the literature, whenever a comparison is meaningful.
{"title":"Full-band-structure theory of high-field transport and impact ionization of electrons and holes in Ge, Si, and GaAs","authors":"M. Fischetti, N. Sano, S. Laux, K. Natori","doi":"10.1109/TCAD.1996.6449160","DOIUrl":"https://doi.org/10.1109/TCAD.1996.6449160","url":null,"abstract":"The empirical pseudopotential band-structure of Ge, Si, and GaAs is used to compute the impact ionization (pair production) rate for electrons and holes. The constant-matrix-element and Kane's random-k approximations are also employed, to assess the importance of the energy-dependence of the Coulomb matrix element, of momentum conservation, and of the joint density of states. For electrons in Si and electrons and holes in Ge and GaAs, the latter is found to be dominant, while for holes in Si momentum conservation appears to be an important constraint on ionization processes near threshold. These results are then fitted to an isotropie ionization rate, function of carrier energy only. Full-band-structure Monte Carlo simulations are finally performed in order to calibrate the acoustic and nonpolar-optical deformation potentials. The low-energy deformation potentials are obtained from the usual1 fits to experimental velocity-field characteristics, while high-energy deformation potentials are determined from fits to experimental data on the ionization coefficients. The usual ambiguity of conventional Monte Carlo calibration of the scattering parameters ∼ using both carrier-phonon and impact ionization rates as fitting entities ∼ is thus removed, giving us better confidence on the final result. The deformation potentials so obtained are in good agreement with those reported in the literature, whenever a comparison is meaningful.","PeriodicalId":100835,"journal":{"name":"Journal of Technology Computer Aided Design TCAD","volume":"25 1","pages":"1-50"},"PeriodicalIF":0.0,"publicationDate":"1996-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"72898030","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1996-01-01DOI: 10.1007/978-3-7091-6827-1_21
B. Govoreanu, W. Schocnmaker, G. Kopalidis, G. Dima, O. Mitrea, M. Profircscu
{"title":"A hybrid technique for TCAD modeling and optimization","authors":"B. Govoreanu, W. Schocnmaker, G. Kopalidis, G. Dima, O. Mitrea, M. Profircscu","doi":"10.1007/978-3-7091-6827-1_21","DOIUrl":"https://doi.org/10.1007/978-3-7091-6827-1_21","url":null,"abstract":"","PeriodicalId":100835,"journal":{"name":"Journal of Technology Computer Aided Design TCAD","volume":"67 1","pages":"1-9"},"PeriodicalIF":0.0,"publicationDate":"1996-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"72913445","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1996-01-01DOI: 10.1109/TCAD.1996.6449172
A. Pardhanani, G. Carey
We investigate numerical integration, preconditioning, iterative solution and multigrid strategies for a class of réaction-diffusion systems used for modeling nonequilibrium phosphorus diffusion in silicon. These problems typically yield stiff systems of equations, and their efficient numerical simulation requires the use of stable integration strategies along with fast, robust algebraic system solvers. We compare the numerical performance of semi-implicit Runge-Kutta methods in conjunction with several standard nonsymmetric iterative solvers and multigrid methods. Our results demonstrate that block-diagonal preconditioning with node-based assembly of the discrete system dramatically improves the performance of iterative solvers. Numerical studies also reveal some interesting new aspects regarding the choice of integration schemes when using iterative methods to solve the linear systems. Unlike the case of direct solvers, where higher-order integration methods typically yield higher computational efficiency, the use of iterative solvers can significantly change or even reverse this trend.
{"title":"Time-integration and iterative techniques for semiconductor diffusion modeling","authors":"A. Pardhanani, G. Carey","doi":"10.1109/TCAD.1996.6449172","DOIUrl":"https://doi.org/10.1109/TCAD.1996.6449172","url":null,"abstract":"We investigate numerical integration, preconditioning, iterative solution and multigrid strategies for a class of réaction-diffusion systems used for modeling nonequilibrium phosphorus diffusion in silicon. These problems typically yield stiff systems of equations, and their efficient numerical simulation requires the use of stable integration strategies along with fast, robust algebraic system solvers. We compare the numerical performance of semi-implicit Runge-Kutta methods in conjunction with several standard nonsymmetric iterative solvers and multigrid methods. Our results demonstrate that block-diagonal preconditioning with node-based assembly of the discrete system dramatically improves the performance of iterative solvers. Numerical studies also reveal some interesting new aspects regarding the choice of integration schemes when using iterative methods to solve the linear systems. Unlike the case of direct solvers, where higher-order integration methods typically yield higher computational efficiency, the use of iterative solvers can significantly change or even reverse this trend.","PeriodicalId":100835,"journal":{"name":"Journal of Technology Computer Aided Design TCAD","volume":"50 1","pages":"1-12"},"PeriodicalIF":0.0,"publicationDate":"1996-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"78822728","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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