Effects of various surface treatments on gate leakage, subthreshold slope, and current collapse in AlGaN/GaN high-electron-mobility transistors

The reduction in the gate leakage current and the improvement in subthreshold characteristics and current collapse in AlGaN/GaN high-electron-mobility transistors (HEMTs) with various surface treatments were investigated. We applied wet treatment, digital etching (O 2 or N 2 O), or plasma treatment (CF 4 or SF 6 ) before SiN x passivation. Among these treatments, SF 6 plasma treatment suppressed gate leakage current, reduced subthreshold slope, and improved pulsed current–voltage ( I – V ) characteristics most effectively.