TCAD Modelling of Anisotropic Channel Mobility in 4H-SiC MOSFETs

Channel mobility is one of the most critical parameters in 4H-SiC based Power MOSFETs and contributes a significant fraction of device on-state resistance. Experimentally, it has been shown that the a-face channel mobility is much higher compared to the Si-face, making a-face a very attractive option for a wide range of applications in the power electronics market. However, modelling of the a-face channel mobility using Technology Computer Aided Design tools is not well established due to the complex nature of channel mobility due to a variety of scattering mechanisms involved. In this paper, we present a well calibrated a-face channel mobility model that shows an excellent match with the available experimental data and further provides critical insights into the anisotropic nature of channel mobility in 4H-SiC MOSFET structures.