Short circuit capability and high temperature channel mobility of SiC MOSFETs

Abstract

Short circuit capability of a 1200V SiC MOSFET and a 1200V Si IGBT is compared and analyzed in this work, and the channel mobility in the SiC MOSFET over a broad temperature range from room temperature up to 2000 °C has been extracted for the first time. Experimental results show that SiC MOSFET exhibits shorter short circuit withstand time (SCWT) compared to Si IGBT. 1-D transient finite element thermal models of SiC MOSFETs and Si IGBTs have been implemented to simulate the dynamic temperature profiles in devices during short circuit tests. The junction temperature of SiC MOSFET rises much faster than that of Si IGBT and the heat spreading thickness of SiC MOSFET is much narrower, leading to shorter SCWT of the SiC MOSFET. Combining the experimental and thermal simulation results, the temperature-dependent saturation drain current in SiC MOSFETs is extracted. Based on this, the channel mobility over a wide temperature range is obtained.