Annealing of proton and alpha particle damage in Au-W/β-Ga₂O₃ rectifiers

Vertical geometry Ga₂O₃ rectifiers were irradiated with 18 MeV alpha particles to fluences of 1-3 × 10¹³ cm^-2 or 10 MeV protons to fluences of 1-3 × 10¹⁴ cm^-2 and then annealed to establish the thermal stability of the radiation damage. The rectifiers employed Au/W rectifying contacts to achieve the requisite thermal stability to allow for annealing studies. The carrier removal rates were ∼900 cm^-1 for the α-particles and ∼200 for the protons. Annealing at 500°C was found to restore the carrier concentration in the α-particle irradiated devices, while 450°C annealing brought substantial recovery of the proton irradiated devices. This is a similar temperature range as established for annealing of plasma-induced damage in Ga₂O₃, suggesting a common origin of point defects, predominantly Ga vacancies and their complexes. The reverse breakdown voltages and diode on/off ratios are also significantly recovered by annealing after irradiation.