Oxygen vacancies and local amorphization introduced by high fluence neutron irradiation in β-Ga₂O₃ power diodes

Beta phase gallium oxide (β-Ga₂O₃) is emerging as a promising material for space applications due to its unique properties and potential high performance in extreme environments. In this work, we systematically study the impact of β-Ga₂O₃ Schottky barrier diodes (SBDs) under a high fluence neutron irradiation to explore the degradation mechanism of the devices. After irradiated by neutrons with an average energy of 1–2 MeV and a dose rate of 1.3 × 10¹² cm⁻² s⁻¹, SBDs with a homoepitaxial layer suffered serious performance degradation. The main manifestation of this degradation was a substantial increase in on-resistance, which rose from 3.9 to 3.5 × 10⁸ mΩ·cm² under the aforementioned irradiation conditions. The appearance of amorphous/polycrystalline striped lattice damage in the epitaxial layer as well as the presence of deep-level defects caused by oxygen vacancies are factors related to this phenomenon. The simulation revealed that the capture reaction of neutrons and Ga elements is the primary cause of neutron irradiation. This reaction generates high-energy beta- particles (β-particles) resulting in the formation of defects. This paper reveals the degradation mechanism of β-Ga₂O₃ SBDs under neutron irradiation and provides a possible design roadmap for radiation-resistant β-Ga₂O₃ power devices. Moreover, a high-temperature oxygen annealing process was implemented, which proved to be in restoring the device performance.