A numerical method for the determination of isotropic band models has been developed and applied to silicon. The resulting model accurately approximates both density of states and group velocity of the corresponding anisotropic band structure, thus providing an excellent agreement with both the collision and nonhomogeneous terms of the Boltzmann transport equation. The model, represented by a simple set of energy-wave vector tables, has been implemented in a Monte Carlo device simulator, but can also be extended to alternative methods for solving the Boltzmann equation. Simulation of homogeneous silicon shows a very good agreement with available experimental data. Comparison with results obtained using the complete anisotropic band structure, both in homogeneous and nonhomogeneous silicon devices, confirms the validity of the model.>

Monte Carlo simulations of high-energy electrons and holes in Si n-MOSFETs are presented. Key features of this work include the use of a suitable silicon model for carrier transport at high electric fields, an original impact ionization model, and sophisticated numerical techniques to speed up the calculation. The case of submicrometer Si n-MOSFETs is considered as a relevant application.>

An efficient self-consistent device simulator coupling Poisson equation and Monte Carlo transport suitable for general silicon devices, including those with regions of high doping/carrier densities, is discussed. Key features include an original iteration scheme and an almost complete vectorization of the program. The simulator has been used to characterize nonequilibrium effects in deep submicron nMOSFETs. Substantial overshoot effects are noticeable at gate lengths of 0.25 mu m at room temperatures.>

An efficient Monte Carlo device simulator has been developed as a postprocessor of a two-dimensional numerical analyzer based on the drift-diffusion model. The Monte Carlo package analyzes real VLSI MOSFETs in a minicomputer environment, overcoming some existing theoretical and practical problems. In particular, the particle free-flight time distribution is obtained by a new algorithm, leading to a CPU time saving of at least one order of magnitude compared with the traditional approach. To describe rare electron configurations, such as the high-energy tails of the distributions and the particle dynamics in the presence of large retarding fields, a multiple repetition scheme was implemented. Selected applications are presented to illustrate the simulator's capabilities.>

The latchup behavior of a VLSI CMOS technology using hybrid Schottky-ohmic contact sources and drains and a high resistivity substrate has been extensively studied via two dimensional numerical simulation. The modeling allows quantitative explanation of the triggering and sustaining behavior of such structures, as well as an accurate characterization of the influence of the various process and geometrical parameters on the resistance to latchup. The technology is compared to a corresponding low resistivity substrate (epi) CMOS technology.