Performance enhancement and defect evolution in β-Ga₂O₃ Schottky barrier diodes induced by 170 keV proton irradiation

The radiation effect of electrical performance and defect evolution in n-type β-Ga₂O₃ Schottky barrier diodes (SBDs) were investigated using 170keV proton irradiation. Results show that J–V characteristics exhibit a reduction in turn-on voltage and an evident enhancement in forward current density along with an increase in carrier concentration, induced by irradiation. In combination with deep level transient spectroscopy (DLTS) characterization, it is observed that an evolution of intrinsic defects is primarily related to proton-implantation. In transient spectra, the strength of peak E1 (Ec − 0.46eV) is significantly reduced, while that of peak E2 (Ec − 0.60eV) is enhanced. Therefore, the evolution of defects is inevitably attributed to the energy loss and dynamic collision of incident protons, which is supported by the characterization of x-ray photoelectron spectroscopy. Based on our built-in defect database of β-Ga₂O₃, it is inferred that E1 represents divacancy V_GaII − V_OII or V_GaI − V_OI and E2 represents trivacancy V_GaII − 2V_OII, V_GaI − 2V_OII, or V_GaI − 2V_OIII. Because of a much deeper charge transition level for majority carriers far from conduction band, DLTS cannot detect the carrier release of hydrogen-passivated gallium vacancies at finite temperature. We found that low-energy proton irradiation can enhance the electrical performance of β-Ga₂O₃ SBDs, whose physical mechanism is clearly elucidated through hydrogen-promoted defect evolution.