Failure mechanisms of AlGaN/GaN HEMTs irradiated by high-energy heavy ions with and without bias

Gallium nitride (GaN)-based devices have significant potential for space applications. However, the mechanisms of radiation damage to the device, particularly from strong ionizing radiation, remains unknown. This study investigates the effects of radiation on p-gate AlGaN/GaN high-electron-mobility transistors (HEMTs). Under a high voltage, the HEMT leakage current increased sharply and was accompanied by a rapid increase in power density that caused "thermal burnout" of the devices. In addition, a burnout signature appeared on the surface of the burned devices, proving that a single-event burnout effect occurred. Additionally, degradation, including an increase in the on-resistance and a decrease in the breakdown voltage, was observed in devices irradiated with high-energy heavy ions and without bias. The latent tracks induced by heavy ions penetrated the heterojunction interface and extended into the GaN layer. Moreover, a new type of N2 bubble defect was discovered inside the tracks using Fresnel analysis. The accumulation of N2 bubbles in the heterojunction and buffer layers is more likely to cause leakage and failure. This study indicates that electrical stress accelerates the failure rate and that improving heat dissipation is an effective reinforcement method for GaN-based devices.