Reverse-Bias Degradation of AlGaN/GaN Vertical Schottky Diodes: An Investigation Based on Electrical and Capacitive Measurements

We present an extensive analysis of the degradation of AlGaN/GaN heterostructures submitted to reverse-bias stress, based on C-V measurements. The analysis was carried out on vertical Schottky diodes. These structures allowed us (i) to achieve a full description of the degradation process, based on C-V measurements (thanks to their large area), and (ii) to accurately control the electric field over the AlGaN and GaN layers, thanks to the vertical contact scheme. Results provide information on the origin of reverse-bias degradation of AlGaN/GaN heterostructures, on the location of the traps generated as a consequence of stress, and on the dependence of the degradation kinetics on the electric field over the AlGaN layer.