Impact of carrier injections on the threshold voltage in p-GaN gate AlGaN/GaN power HEMTs

Abstract

We investigated the threshold voltage (V TH) shift in p-GaN gate AlGaN/GaN power HEMTs under both forward and reverse gate bias conditions at different temperatures. With increasing forward gate bias, the V TH first positively shifted and then decreased. While at the reverse gate bias, V TH shifts monotonically increased towards the positive direction. Positive V TH shifts were due to electron trapping while its decrease was attributed to the optical pumping by the internal electroluminescence (EL). The EL emission from the p-GaN gate region was captured. A light illumination test was performed to verify the effectiveness of optical pumping.