Modeling of carrier scattering in MOS inversion layers with large density of interface states and simulation of electron Hall mobility in 4H-SiC MOSFETs
Hajime Tanaka, Nobuya Mori
Abstract
Abstract We formulate scattering mechanisms in quasi-two-dimensional systems with a large density of interface states such as 4H-SiC MOS interfaces, and calculate the electron Hall mobility in 4H-SiC MOS inversion layers by Monte Carlo simulation. In addition to phonon, ionized impurity, and surface roughness scattering, we take account of Coulomb scattering by the electrons trapped at the interface states and the interface fixed charges and scattering by electrically neutral defects. Considering that the number of trapped electrons can be comparable to or larger than that of mobile electrons, the trapped electrons are assumed to contribute to screening as well as scattering. Using the developed model, we analyze the dependence of Hall mobility in 4H-SiC MOS inversion layers on the body acceptor density, temperature, and interface state density. Our calculation reasonably reproduces the experimental behaviors of Hall mobility. We also discuss the physical mechanisms underlying the obtained results.