Microwave Low-Noise Performance of 0.17~\mu \text Gate-Length AlGaN/GaN HEMTs on SiC With Wide Head Double-Deck T-Shaped Gate

Microwave low-noise performance AlGaN/GaN HEMT on a SiC substrate with a wide head double-deck T-shaped gate has been reported. The HEMTs with gatelength (L g ) of 0.17 μm and source-drain spacing (L sd ) of 3.5 μm exhibited a maximum extrinsic transconductance of 360 mS/mm, a current gain cutoff frequency (f T ) of 50 GHz, a maximum oscillation frequency (f max ) of 149 GHz, and three-terminal breakdown voltage of 113 V. The device exhibited a minimum noise figure (NF min ) of 0.50 and 0.84 dB at 10 and 18 GHz, respectively, when biased at V ds = 5 V and I ds = 140 mA/mm, which is the lowest noise characteristics ever reported for the GaN-based T-shaped gate HEMTs with gate length larger than 0.1 μm. This excellent noise performance is attributed to the reduction of the gate resistance resulting from a wide head T-shaped gate and the improved device characteristics.