High-performance AlGaN/GaN high electron mobility transistors on SiC

AlGaN/GaN high electron mobility transistors (HEMTs) grown on semi-insulating SiC substrates with a 0.12μm gate length have been fabricated. These 0.12μm gate length devices exhibited maximum drain current density as high as 1.23 A/mm and peak extrinsic transconductance of 314 mS/mm. A unity gain cut-off frequency (f_T) of 121 GHz and maximum frequency of oscillation (f_max) of 162 GHz were measured for these devices. These f_T and f_max values are the highest ever reported values for GaN-based HEMTs. Also, a continuous-wave (CW) output power density of 4.2 W/mm with an associated gain of 7.5 dB and a power-added-efficiency (PAE) of 26.4% were obtained at 20 GHz.