Reliability Assessment Of AlGaN/GaN HEMTs on the SiC Substrate Under the RF Stress

Abstract

This article reports a reliability study on AlGaN/GaN high-electron-mobility transistors under the RF stress. It shows a stabilization of the gate contact after the aging test. However, the degradation of RF performances and dc parameters is noticed. The degradations are mainly due to bulk traps located between gate-source or gate-drain and caused by hot-electron effects. The trap-related phenomena results in a reduction of the drain current and RF output power accompanied with transconductance degradation and pinch-off shift. These traps are characterized by gate-lag and drain-lag measurements and spectral photon emission microscopy. Photo emission measurements reveal an inhomogeneous distribution of light and the presence of native traps that could be related to crystallographic defects such as dislocations or impurities.