Study on the effects of proton irradiation on the dc characteristics of AlGaN/GaN high electron mobility transistors with source field plate

Abstract

The effects of proton irradiation dose on the dc characteristics of AlGaN/GaN high electron mobility transistors (HEMTs) with source field plates were studied. The HEMTs were irradiated with various protons doses ranging from 5 x 10(12) to 5 x 10(15) cm(-2) at a fixed energy of 5 MeV. HEMTs irradiated with proton dose below 5 x 10(13) cm(-2) showed less than 2% degradation of either saturation drain current (I-DSS) or transconductance (g(m)). Significant changes of these parameters were observed for the devices irradiated with doses above 5 x 10(13) cm(-2). HEMTs irradiated with the highest proton dose of 5 x 10(15) cm(-2) showed a reduction of I-DSS and g(m) of 86% and 64.7%, and a positive V-th shift of 0.84 V, respectively. Despite the significant I-DSS and g(m) reductions, the off-state drain breakdown voltage (V-BR) was improved more than five times at this particular irradiation condition. The significant improvement of off-state drain breakdown voltage was attributed to the formation of a virtual gate at drain side of gate edge, which was the result of the generation of defect centers at AlGaN/GaN interface. (C) 2014 American Vacuum Society.