Toward a physical understanding of the reliability-limiting E C -0.57 eV trap in GaN HEMTs

Recent reliability testing campaigns on AlGaN/GaN HEMTs have consistently revealed a critical E C -0.57 eV trap that is responsible for drain-lag, RF output power degradation, and current-collapse among other non-idealities. In this work, a comprehensive set of data obtained from a range of measurements and specialized test structures are combined and presented to reveal compelling evidence that this nearly ubiquitous degradation-causing defect in GaN HEMTs is physically located in the GaN buffer.