Demonstration of high output power (3.75 W/mm) with 31.8% PAE in Ga-Polar AlGaN/GaN HEMTs on sapphire at 94 GHz

In this work, a recessed-gate Ga-polar AlGaN/GaN high-electron-mobility transistor (HEMT) on sapphire incorporating an AlGaN back-barrier for W-band operation is demonstrated. The device achieves a subthreshold slope of ~130 mV/dec, a peak transconductance of 0.75 S/mm, and an fmax exceeding 240 GHz