(Invited) Radiation Damage in the Ultra Wide Bandgap Semiconductor Ga₂O₃

Abstract

β-Ga 2 O 3 is attractive for high temperature applications in harsh environments that cannot be tolerated by conventional electronics. Its wide bandgap allows operation at elevated temperatures, while it is also radiation hard. Radiation tolerance is an important factor while fabricating microelectronics and typical radiation damage suffered includes total dose effects, displacement damage, and single event effects. Ga 2 O 3 appears to be more resistant to displacement damage than GaN and SiC, as expected from a consideration of their average bond strengths. EPR results of neutron irradiated, bulk samples suggested that octahedral gallium monovacancy defects were the main defects produced. Proton irradiation introduces two main paramagnetic defects in Ga 2 O 3 , which are stable at room temperature. Charge carrier removal can be explained by Fermi-level pinning far from the conduction band minimum due to gallium interstitials (Ga i ), vacancies (V G a ), and antisites (Ga O ). While there are no experimental or simulation results for single event effects in Ga 2 O 3 to this point, it has become worryingly apparent that while other wide bandgap semiconductors like SiC and GaN are robust against displacement damage and total ionizing dose, they display significant vulnerability to single event effects at high Linear Energy Transfer (LET) and at much lower biases than expected. We have also analyzed the transient response of β-Ga 2 O 3 SBDs to heavy-ion strikes via TCAD simulations to understand the effect of various structural parameters. Using field metal rings has been reported to improve the breakdown voltage of these devices and biasing those rings can help control the breakdown voltage of the device. We find that such biased rings help in the removal of the charge deposited by the ion strike.