Ka-Band MMIC Using AlGaN/GaN-on-Si With Recessed High- ${k}$ Dual MIS Structure

This letter reports the excellent radio frequency output characteristics of AlGaN/GaN-on-Si power amplifier (PA) monolithic microwave integrated circuits (MMICs) operating at the Ka-band, employing a recessed metal-insulator-semiconductor (MIS) structure with SiN
_x
/HfON dual dielectric layers. The fabricated 0.15-μm AlGaN/GaN-on-Si high electron-mobility transistor (HEMT) exhibited a low OFF-state current and reduced current collapse in comparison with the conventional Schottky gate HEMT; therefore, an enhanced output power of the PA MMIC is achieved. The fabricated two-stage PA MMIC exhibited a continuous-wave output power of >29 dBm with a power-added efficiency (PAE) of 14.5% at the drain voltage of 20 V, at 26.5 GHz.