High-power and efficiency W-band InAlGaN/AlN/GaN high-electron-mobility transistors for future high-capacity wireless communications

This study describes high-power and high-efficiency W-band InAlGaN/AlN/GaN high-electron-mobility transistors (HEMTs) for future sub-terahertz wireless communications. A low-thermal-budget selective-area growth (SAG) process was developed to obtain low contact resistance with low trap states. Transmission lines and substrate structures were optimized to obtain high-thermal conductivity and low substrate resonance. Consequently, a high output power of 28.7 dBm (742 mW), output power density of 4.6 W mm⁻¹, and power-added efficiency (PAE) of 28.0% were achieved with pre-matched InAlGaN/AlN/GaN HEMTs at 90 GHz, which were superior combination of output power and PAE compared to the conventional high-temperature SAG process.