Catastrophic burnout mechanisms of NiO/β-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 (E_V + 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.