Evidence for breakdown luminescence in AlGaN/GaN HEMTs

With this paper we present a detailed analysis of the electrical and optical properties of AlGaN/GaN HEMTs in the breakdown regime. By means of a wide set of measurements carried out at different voltage and current conditions, we show that: (i) when HEMTs are biased in pinch-off conditions, and in current-controlled mode, they can reach a non-destructive breakdown condition; (ii) during non-destructive breakdown devices emit a weak luminescence signal, in proximity of the drain edge; (iii) breakdown voltage (BDV) has a non-monothonic dependence on the gate voltage level and on temperature.