ANALYTICAL MODEL FOR THE DC Ⅰ-Ⅴ CHARACTERISTICS OF N-CHANNEL 4H-SiC MOSFET BASED ON SURFACE POTENTIAL

摘要

Based on the charge-sheet approximation, an improved physical-based analytical model for the DC Ⅰ-Ⅴ characteristics of n-channel 4H-SiC MOSFET that incorporates the drift and diffusion currents is presented considering the influences of the incomplete ionization of the dopant impurities and the non-uniform distribution of interface state density. The surface potential is obtained numerically by using the Newton-Raphson method after an analytical solution of the one-dimensional Poisson equation for the electric field at the semiconductor surface. The simulation and measurement results are in good agreement with each other. The model is simple in calculations and distinct in physical mechanism, therefore suitable for predicting the behavior of the 4H-SiC MOSFET prior to actual device fabrication.