A NUMERICAL-METHOD TO COMPUTE ISOTROPIC BAND MODELS FROM ANISOTROPIC SEMICONDUCTOR BAND STRUCTURES

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 to both the collision and non-homogeneous terms of the Boltzmann transport equation. The model, represented through a simple set of energy-wave vector tables, has been implemented into a Monte Carlo device simulator, but can also be extended to alternative methods for solving 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 non-homogeneous silicon devices, confirms the validity of the model.