Kinetic approach to barrier capacitance calculation and its application to modelling of microstructures with metal-semiconductor junctions

摘要

Non-uniform doping profiles are typical of modern microstructures. The conventional procedure used in computer simulation of capacitance-voltage (C-V) characteristics and C-V profiling is a quasistatic method based on solving a nonlinear Boltzmann-Poisson equation. This method includes the free carrier thermal motion, which is very important for microstructures. At the same time, it is strictly formal and employs numerical derivatives. From a mathematical standpoint, it is an ill-posed problem. TO eliminate the disadvantages of the method, we propose another theoretical approach to barrier capacitance, inspired by two sources : small-signal modelling of the capacitor response and an averaging method for calculating values used in physical kinetics. This kinetic approach permits closer physical analysis of the C--V characteristics. Furthermore, the computer simulation technique based on this approach offers a great advantage over the quasistatic method in accuracy and efficiency. The results of computer simulation demonstrate the possibility of developing a technique for forward and inverse modelling.