Improved reverse recovery characteristics of low turn-on voltage AlGaN/GaN Schottky barrier diodes with anode edge AlON spacers

Low reverse recovery charge and low turn-on voltage AlGaN/GaN Schottky barrier diodes were fabricated on a 6-inch Si (111) substrates using a recessed anode and N₂O plasma-oxidized AlON compound spacer. The N₂O plasma-treated areas at the anode edge were oxidized because the AlON passivation layers and spacers under the field plate metals formed a favorable interface with the GaN layer that reduced the nitrogen vacancies and surface leakage currents. Relative to traditional recessed barrier diodes, the barrier diodes fabricated with a recessed anode and an AlON compound spacer realized a higher breakdown voltage (825 V), lower specific on-resistance (3.36 mΩ-cm²), and lower turn-on voltage (0.43 V). In addition, the reverse recovery and low-frequency noise measurements indicated that the N₂O plasma-oxidized AlON compound spacer reduced the surface traps from the plasma bombardment during the anode recess process and improved the carrier confinement in the two-dimensional electron gas channel.