Investigation of the effect of temperature during off-state degradation of AlGaN/GaN High Electron Mobility Transistors

► AlGaN/GaN HEMTs exhibit a negative temperature dependence for V CRI. ► Breakdown at V CRI does not occur immediately with applied bias. ► DC stress results in consumption of interfacial oxide layer. ► Low activation energy of 42 meV. AlGaN/GaN High Electron Mobility Transistors were found to exhibit a negative temperature dependence of the critical voltage ( V CRI) for irreversible device degradation to occur during bias-stressing. At elevated temperatures, devices exhibited similar gate leakage currents before and after biasing to V CRI, independent of both stress temperature and critical voltage. Though no crack formation was observed after stress, cross-sectional TEM indicates a breakdown in the oxide interfacial layer due to high reverse gate bias.