Effect of 1-MeV Equivalent Neutron Irradiation on the Electrical Characteristic of NiOx/β-Ga2O3 p-n Diode

Abstract

In this article, the impact of 1-MeV equivalent neutron irradiation on the electronic properties of NiOx/beta-phase gallium oxide ( $\beta $ -Ga2 ${\mathrm {O}}_{{3}}\text {)}$ p-n diode has been investigated. After neutron irradiation with a fluence of $1\times 10^{{14}}$ n/cm2, the forward current density ( ${J}_{F}\text {)}$ decreased by 23%, the leakage current density ( ${J}\text {)}$ was reduced by 45.6%, and the breakdown voltage ( ${V}_{\text {br}}\text {)}$ increased by approximately 216 V, as measured by current − voltage (I– ${V}\text {)}$ analysis. The capacitance− voltage (C– ${V}\text {)}$ measurement shows that the carrier concentration in the lightly doped n-type $\beta $ -Ga2O3 drift layer decreased from $1.96\times 10^{{16}}$ to $1.74\times 10^{{16}}$ cm ${}^{-{3}}$ after neutron irradiation. The effect of neutron irradiation on the trap states was studied using frequency-dependent conductivity techniques. It is revealed that the density of trap states at NiOx/ $\beta $ -Ga2O3 increases significantly from 1.12 to $1.49\times 10^{{12}}$ cm ${}^{-{2}}\cdot $ eV ${}^{-{1}}$ to 3.76- $5.80\times 10^{{12}}$ cm ${}^{-{2}}\cdot $ eV ${}^{-{1}}$ , accompanied by a slight decrease in trap activation energy from 0.091 to 0.187 eV to $0.086-0.185$ eV after neutron irradiation. Additionally, deep-level transient spectroscopy (DLTS) measurements indicate that the trap at an energy level of ${E}_{C}$ – ${E}_{T} =0.75$ eV, induced by neutron irradiation, is likely the primary cause of the degradation in NiOx/ $\beta $ -Ga2O3 p-n diode properties. These findings can offer significant theoretical insights for the design of future anti-radiation hardening.