Improved reverse blocking characteristics in AlGaN/GaN Schottky barrier diodes based on AlN template

AlGaN/GaN-based planer Schottky barrier diodes (SBDs) with circular anode configuration were formed on AlN template and on sapphire. SBDs formed on AlN template exhibited clearly improved reverse-blocking characteristics compared with SBDs formed on sapphire. This appears to be due to their high crystal quality realised as a result of using AlN template. Breakdown voltages in those SBDs increased with the anode-to-cathode spacing and reached a high value of approximately 3 kV at a gap-spacing of 50 µm for SBDs formed on AlN template.