Surface-oxide-controlled InGaAs/InAlAs inverted-type metal-oxide-semiconductor high electron mobility transistors for sub-THz high-power amplifiers


 Herein, we successfully improved the maximum oscillation frequency and maximum stable gain (MSG) across a wide bias range of surface-oxide-controlled (SOC) InGaAs/InAlAs inverted-type metal-oxide-semiconductor high-electron-mobility transistors (inverted MOS-HEMTs) by reducing the gate leakage current and drain conductance. H2O vapor treatment selectively decreased the narrow band gap oxide, InOx, at the In-based epitaxial layer surface via SOC before the gate oxide deposition. Consequently, SOC-inverted MOS-HEMTs demonstrated a high MSG of > 12 dB at 100 GHz across a wide bias range.