Subthreshold and turn-on characteristics in Schottky-type p-GaN Gate HEMTs: impact of partially and fully depleted p-GaN layer

Abstract In this work, the impact of partially depleted and fully depleted p -GaN (PDP-GaN and FDP-GaN) layers on the gate characteristics of Schottky-type p -GaN Gate HEMTs is investigated. Four wafers are fabricated via different annealing temperatures to achieve the PDP-GaN and FDP-GaN layers. Devices with PDP-GaN show nearly identical SS / V TH , while G m,max enhances with increased activated Mg concentration. Meanwhile, the device with FDP-GaN demonstrates higher SS , lower V TH , and specific G m,max compared to the others. It turns out that subthreshold and turn-on characteristics are attributed to the position of the Fermi level in p -GaN and the Schottky tunneling leakage current, respectively.