Radiation Effects of 500 MeV Kr+ Ions on NiO/β-Ga₂O₃ Heterojunction Diodes

This study investigates the in-situ radiation effects on NiO/β-Ga₂O₃ heterojunction diodes (HJDs) under 500 MeV Kr⁺ ions irradiation, with a fluence of 1×10⁸ cm^-2 at -200 V. The statistical results show that both the forward conductive and reverse blocking characteristics of the HJDs were degraded after the irradiation of Kr⁺ ions. Associated with the analysis of current-voltage characteristics and the SRIM simulation results, the performance degradations were attributed to the vacancies induced by Kr⁺ ions radiation in the β-Ga₂O₃ material. On the one hand, the Kr⁺ radiation-induced vacancies reduced the net carrier concentration of the β-Ga₂O₃ and increased the generation-recombination current, leading to increased specific on-resistance and ideality factor of the irradiated HJDs. On the other hand, an oxygen di-vacancies-related trap, set at 1.07±0.01 eV below the conduction band, was involved after Kr⁺ ions radiation, which enhanced the Poole-Frenkel emission process, dominating the higher leakage current of the irradiated HJDs beyond -300 V. These results provide valuable insights into the radiation damage and performance degradation mechanisms in β-Ga₂O₃-based devices for space applications.