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 highelectron-mobility transistors (HEMTs) with various surface treatments were investigated. We applied wet treatment, digital etching (O₂ or N ₂O), 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.