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. [Display omitted] •Low Qrr, low VON GaN SBDs were demonstrated using recessed anode and AlON compound spacer.•The N2O treatment on GaN can form AlON compound and filled nitrogen vacancies.•The LFN measurements indicated that the N2O oxidized AlON spacer layer reduce the surface traps.•GaN SBD with AlON spacer layer achieve a good thermal stability.