Gate Current Peaks Due to CGD Overcharge in SiC MOSFETs Under Short-Circuit Test

Abstract

SiC MOSFETs experience a wide variety of electro-thermal phenomena during short-circuit (SC) test. A specific feature that is present in SiC MOSFETs is the high dynamic gate current (iG) which may have an influence on device degradation and failure. In recent SiC MOSFET technologies, the iG waveforms captured during SC testing show previously unexplained peaks. In this paper, the authors investigate the causes of these iG peaks using both experimental data and TCAD simulations, where significant effects of the CGD overcharge are observed. Moreover, an iG comparison between different 1.2 kV device designs are performed with emphasis on best iG sensing practices.