Single-event robustness under pulsed voltage stress and gate degradation under negative gate bias in hybrid-drain gate injection transistors (HD-GITs)

This Letter investigates the single-event effect (SEE) hardness of hybrid-drain gate injection transistors (HD-GITs) under heavy-ion irradiation with pulsed stepping voltage stress. HD-GITs under test exhibit single-event burnout (SEB) thresholds at 450 and 330 V at the linear energy transfer (LET) of 37.9 and 82.1 MeV cm²/mg, respectively. In contrast to the enhanced radiation tolerance observed in Schottky p-GaN gate HEMTs under negative off-state gate bias (V _GSQ), HD-GITs exhibit gate degradation under identical bias conditions. Specifically, SEB threshold decreases from 330 to 300 V at an LET of 82.1 MeV cm²/mg as the off-state V _GSQ shifts from 0 to −4 V. Post-irradiation characterization reveals pronounced gate-drive degradation, particularly under negative V _GSQ bias, as evidenced by substantially elevated gate-drive current. Gate leakage transport analysis indicates that SEE-induced traps at AlGaN/GaN heterojunction preferentially capture holes under negative V _GSQ, generating a localized electric field that initiates a premature Fowler–Nordheim tunneling effect.