Low-Energy Ion-Induced Single-Event Burnout in Gallium Oxide Schottky Diodes

Low-energy ion-induced breakdown and single-event burnout (SEB) are experimentally observed in beta-gallium oxide ( $\beta $ -Ga2O3) Schottky diodes with voltages well below those of expected electrical breakdown. Fundamentally different responses were observed among alpha particle, Cf-252, and heavy-ion irradiation. Technology computer-aided design (TCAD) simulations suggest that ion-induced burnout can be triggered at high voltages as a result of a single ion strike, leading to impact ionization, voltage-induced charge separation accentuated by the low intrinsic hole mobility in $\beta $ -Ga2O3, and breakdown. At significantly lower voltages, the cumulative buildup of displacement-damage-induced defects in $\beta $ -Ga2O3 during high-fluence ion irradiation can lead to defect-driven breakdown due to the generation and motion of negatively charged Ga vacancies and O interstitials. First-principles calculations show that defect clusters can be formed, which are much less resistive than the surrounding material. These clusters can be driven deeply into the device by the reverse bias, ultimately forming conduction paths that can facilitate the destruction of the device at reduced voltages.

I. Introduction

Wide bandgap (WBG) semiconductor devices are ideally suited for high-power electronics due to material properties that provide improved efficiency and reduced size when compared to silicon-based counterparts [1]. These devices can withstand higher voltages and temperatures, with much lower ON-state resistance for a given die size when compared to a silicon equivalent. These characteristics have resulted in significantly more efficient power conversion. While there is a tremendous amount of data and knowledge associated with single-event radiation effects for silicon power devices, there is much less information available for WBG materials [2]. For example, SiC power devices have been shown to be susceptible to heavy-ion exposure, with catastrophic single-event burnout (SEB) occurring at biases as low as 40% of their rated breakdown voltage [3], [4].