Radiation effects of 5 MeV proton on Ni/<i>β</i>-Ga2O3 Schottky barrier diodes

This study investigated the effects of 5 MeV proton irradiation on the static electrical characteristics of Ni/β-Ga2O3 Schottky barrier diodes without and with NiO rings (SBDs and RSBDs), with a total irradiation fluence of 1 × 1013 cm−2. The results indicated that the proton irradiation damage decreased the current level of the SBDs and RSBDs due to the reduced net carrier concentration of β-Ga2O3 by about 50% other than the impact on the Schottky contact. On the one hand, the reduced net carrier concentration increased the on-resistance, resulting in a reduction in the forward saturation current by approximately one order of magnitude. On the other hand, because the leakage current mechanism was dominated by the Poole–Frenkel emission process and Fowler–Nordheim tunneling process, the reduced net carrier concentration degraded the electric fields in the irradiated SBDs and RSBDs, reducing the effect of the NiO guard ring and, meanwhile, leading to a lower leakage current after proton irradiation. In addition to being associated with the temperature-dependent current–voltage (I–V–T) results, the proton irradiation also suppressed the Poole–Frenkel emission process and increased the tunneling barrier height of SBDs and RSBDs. In this case, the breakdown voltage of the SBDs and RSBDs increased by approximately 2–4 times. In addition, the Technology Computer Aided Design simulations showed a reduced discrepancy between the peaks of the electric field of SBDs and RSBDs after irradiation, leading to the comparable leakage current of SBDs and RSBDs, which confirmed the weakening of the NiO guard ring’s effect.