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 (O2 or N2O), or plasma treatment (CF4 or SF6) before SiNx passivation. Among these treatments, SF6 plasma treatment suppressed gate leakage current, reduced subthreshold slope, and improved pulsed current-voltage (I-V) characteristics most effectively.