AIGaN/GaN MIS-HEMTs with f/sub T/ of 194 GHz at 16 K

45 nm-gate AlGaN/GaN MIS-HEMTs on SiC substrates have been fabricated and their DC and RF characteristics measured at 300 and 16 K. A source-drain spacing Lsd of 1.5 µm was used to reduce parasitic resistances, which was 0.5 µm shorter than that in previous work. High cutoff frequency fT values of 156 GHz at 300 K and 194 GHz at 16 K were obtained. These fT values are about 10% higher than those of AlGaN/GaN MIS-HEMTs with an Lsd of 2 µm.