Laser-Induced Single-Event Burnout in GaN Devices

Single-event effects (SEEs), specifically single-event transient (SET) and single-event burnout (SEB), in GaN high electron mobility transistors (HEMTs) and vertical GaN diodes were studied using ultrafast laser pulses. By utilizing single-photon and two-photon absorption techniques, we determined the crucial role of material defects and high electric field regions - such as gate edges in the drain access area (GaN HEMTs) or area near the edge of anode contacts (GaN vertical diodes), in enhancing single-event burnout (SEB) susceptibility. Focusing laser light on these sensitive regions significantly increases susceptibility to SEB well below the operational breakdown voltage of the device. We identified the growth-related defects areas acting as high-field "hot spots". The spatial selectivity of pulsed laser allowed targeted irradiation of these defect-rich regions. A focused laser light can induce a rise in leakage current, eventually leading to device burnout. The increased sensitivity to SEB observed in GaN material containing defects suggests that the pulsed laser can be used to screen devices for SEB vulnerability.