Analysis of the post-stress recovery of reverse leakage current in GaN HEMTs

Abstract The recovery of high reverse gate leakage current in AlGaN/GaN HEMTs has been analyzed in this study. To demonstrate the recovery after a thermal stress for large time periods (8–12 h), two mechanisms: phonon assisted tunnelling (PAT) and trap assisted tunnelling (TAT) have been utilized. Charge-based analytical models from literature have been used to match experimental leakage currents in reverse bias conditions. The degradation in the devices has been activated through thermal stress and the effect of high electric field induced inverse piezo electric effect has been eliminated. PAT component shows dominance in higher temperature regime (T > 500 K) and the slow recovery at 300 K with characteristic τ values around 5–13 h has been attributed to the TAT component through a deep trap level within the AlGaN barrier.