Catastrophic burnout mechanisms of NiO/<b> <i>β</i> </b>-Ga2O3 heterojunction diodes irradiated by 1.35 GeV high-energy heavy ions

Ultra-wide bandgap beta-phase gallium oxide (β-Ga2O3) power devices hold great promise in space applications; however, their intrinsic vulnerability to heavy ion irradiation, particularly defect behavior and catastrophic burnout mechanisms, remains largely unexplored. By performing bias voltage-dependent multiple rounds of statistical experiments with 1.35 GeV high-energy Ta ion irradiation, this work identifies electron and hole traps before burnout in NiO/β-Ga2O3 heterojunction diodes (HJDs), among which the introduced hole trap H2 (EV + 0.6 eV, 2.9 × 1013 cm−3) is revealed to dominate the irrecoverable leakage degradation associated with device damage by deteriorating the junction barrier. This trap in Ga2O3 is attributed to the electron energy loss along the ion incidence trajectory based on the “thermal spike” physics theory, possibly resulting in a localized amorphous latent track. Beyond device damage, the catastrophic burnout in irradiated HJD is identified in two distinct regions: Region I (p-NiO/n−-Ga2O3) dominated by trap-assisted electric field breakdown, and Region II (n−-Ga2O3/n+-Ga2O3) characterized by thermally driven damage from charge accumulation. Additionally, thermal effects also impact the active area of Region I along the carrier dissipation pathway. These findings provide insight into the damage and failure physics of β-Ga2O3 devices under heavy-ion strikes and inform strategies for improved irradiation hardness.