Investigation of drain current injection-induced degradation and mechanisms in Schottky gate AlGaN/GaN HEMTs

Abstract In this work we investigate the degradation of electrical parameters and the variation in injection-induced leakage current paths of Schottky gate AlGaN/GaN high-electron-mobility transistors (HEMTs) subjected to long-term drain current injection (DCI) stress. The underlying mechanisms are also elucidated through static and transient technology computer-aided design simulations. Our results reveal that the injection-induced gate leakage current causes electron trapping within the AlGaN layer beneath the gate. This trapping process leads to the degradation of key electrical parameters, including a positive shift in threshold voltage ( V TH ), an increase in on-resistance ( R on ), a reduction in both off-state gate leakage current and reverse gate current and a shift of the DCI breakdown curve towards a higher drain-to-source voltage ( V DS ). Furthermore, the trapping process enhances the reverse current blocking capability of the gate, thus the injection-induced gate leakage current is reduced while the injection-induced buffer leakage current increases, which causes a continuous increase V DS and ultimately results in device failure.