Effect of 20 MeV proton irradiation on the electrical properties of NiOx/<i>β</i>-Ga2O3 p–n diodes

In this article, the impact of 20 MeV proton irradiation on NiOx/β-Ga2O3 p–n diodes has been investigated. After 20 MeV proton irradiation with a fluence of 2 × 1012 p/cm2, the forward current density (JF) decreased by 44.1% from 93.0 to 52.0 A/cm2, and the turn-on voltage (Von) increased from 1.55 to 1.68 V based on current–voltage (I–V) measurements. Moreover, the capacitance–voltage (C–V) measurements indicated that the net carrier concentration in the β-Ga2O3 lightly doped drift region was reduced from 1.95 × 1016 to 1.86 × 1016 cm−3 after proton irradiation. The effect of proton irradiation on NiOx/β-Ga2O3 interface trap states was also acquired utilizing the frequency-dependent conductance technique. The results indicated that the time constant increased from 0.04–0.15 to 0.13–0.23 μs after proton irradiation. Meanwhile, it was found that the density of interface trap states increases from 7.49 × 1010–1.27 × 1010 to 7.23 × 1011–1.70 × 1012 cm−2 eV−1 with an increase in trap activation energy from 0.080–0.111 to 0.088–0.121 eV after proton irradiation. This work provides an important reference for further improving the performance of NiOx/β-Ga2O3 p–n diodes through the design of subsequent anti-radiation hardening.