Exploring current conduction mechanisms in 6 MeV $\text{Si}^{3+}$ ion irradiated Au/SiO2/beta-Ga2O3 metal-oxide-semiconductor devices

Abstract

Wide bandgap and cost-effective features place Ga2O3 as a viable candidate for various power electronic devices. Au/SiO2/beta-Ga2O3 metal-oxide-semiconductor devices are tested for radiation response with 6 MeV $\text{Si}^{3+}$ ions. The leakage current density is found to increase from $8.6\times 10^{-5} \mathrm{A}/\text{cm}^{2}$ (for pristine device) to $9.8\times 10^{-4}\mathrm{A}/\text{cm}^{2}$ (at $5\times 10^{16}\ \text{ions}/\text{cm}^{2}$ fluence) at −10 V. Various current conduction mechanisms are explored under gate and substrate injection in these devices. Under gate injection, the direct tunneling dominates at low voltage regime of 0 to −3 V at all fluences due to low SiO2 thickness $(\sim 10\ \text{nm})$. The Poole-Frenkel emission is quite dominant at $5\times 10^{16}\text{ions}/\text{cm}^{2}$ attributed to the increased number of trap states in SiO2, and the estimated shallow trap depth is 0.4 (pristine) to 0.2 eV (highest fluence) from the conduction band edge. The barrier height (BH) of SiO2/beta-Ga2O3 interface estimated from the Fowler-Nordheim tunneling under substrate injection is 2.52 eV for the pristine device and the BH is found to decrease to 1.83 eV at $1\times 10^{16}\ \text{ions}/\text{cm}^{2}$ fluence.