Thermal stability and annealing of intrinsic point defects in beta-Ga₂O₃

Gallium oxide, especially in the β-phase, emerges as a transformative material for high-power semiconductor applications. However, despite its promising attributes, it is still in an exploratory phase. The present article delves into the transport properties and their modifications induced by low-temperature electron irradiations, which generate point defects that affect the electrical properties of the material. The methodology involves post-irradiation isochronous annealing of n-type β-Ga₂O₃ samples up to 573 K, which allows the study of defect thermal stability. Results reveal that annealing is able to induce a total recovery of conductive properties after electron irradiation-induced n-type to insulator transition. While this behavior may limit the use of irradiation-treated materials for high-power device realization, it highlights the self-healing properties in gallium oxide which would be subjected to radiation damage. In-situ experiments performed from 22 to 250 K have proved that relevant modifications of electrical properties take place upon warming up the sample after 22 K irradiation. Such data suggest the presence of defects with high mobility. Even room temperature defects do not survive thermal treatments at a few hundred degrees Celsius (approximately 530 K).