Physics for numerical simulation of silicon and gallium arsenide transistors

Abstract

The motivation for using computers to simulate the electrical characteristics of transistors is discussed. Our work and that of others in the area of device physics and modeling is described. We compare conventional device physics with an alternative approach to device physics that is more directly traceable to quantum-mechanical concepts. We then apply this new approach to quasi-neutral regions, space-charge regions, and regions with high levels of carrier injection. The limits for using theoretical results from uniform media in numerical simulations of devices with large concentration gradients are discussed. New calculations of the effective intrinsic carrier concentrations for gallium arsenide and silicon are also given. We conclude with examples of applying quantum-mechanically-based device physics to energy band diagrams for heterojunction bipolar transistors, MOS capacitors, and homojunction bipolar transistors.