Effect of Proton Irradiation on Interface State Density in Sc2O3/GaN and Sc2O3/MgO/GaN Diodes

Abstract

Proton irradiation of Sc2O3/GaN and Sc2O3/MgO/GaN metal-oxide semiconductor diodes was performed at two energies, 10 MeV and 40 MeV, and total fluences of 5 × 109 cm−2, corresponding to 10 years in low-earth orbit. The proton damage causes a decrease in forward breakdown voltage and a flat-band voltage shift in the capacitance-voltage characteristics, indicating a change in fixed oxide charge and damage to the dielectric. The interface state densities after irradiation increased from 5.9 × 1011 cm−2 to 1.03 × 1012 cm−2 in Sc2O3/GaN diodes and from 2.33 × 1011 to 5.3 × 1011 cm−2 in Sc2O3/MgO/GaN diodes. Postannealing at 400°C in forming gas recovered most of the original characteristics but did increase the interfacial roughness.