Point defect induced degradation of electrical properties of Ga2O3 by 10 MeV proton damage

Abstract

Deep electron and hole traps in 10 MeV proton irradiated high-quality beta-Ga2O3 films grown by Hydride Vapor Phase Epitaxy (HVPE) on bulk beta-Ga2O3 substrates were measured by deep level transient spectroscopy with electrical and optical injection, capacitance-voltage profiling in the dark and under monochromatic irradiation, and also electron beam induced current. Proton irradiation caused the diffusion length of charge carriers to decrease from 350-380 mu m in unirradiated samples to 190 mu m for a fluence of 10(14) cm(-2), and this was correlated with an increase in density of hole traps with optical ionization threshold energy near 2.3 eV. These defects most likely determine the recombination lifetime in HVPE beta-Ga2O3 epilayers. Electron traps at E-c-0.75 eV and E-c-1.2 eV present in as-grown samples increase in the concentration after irradiation and suggest that these centers involve native point defects. Published by AIP Publishing.