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

AlGaN/GaN High Electron Mobility Transistors were found to exhibit a negative temperature dependence of the critical voltage (VCRI) for irreversible device degradation to occur during bias-stressing. At elevated temperatures, devices exhibited similar gate leakage currents before and after biasing to VCRI, 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.

► AlGaN/GaN HEMTs exhibit a negative temperature dependence for VCRI.
► Breakdown at VCRI does not occur immediately with applied bias.
► DC stress results in consumption of interfacial oxide layer.
► Low activation energy of 42 meV.