Microwave Low-Noise Performance of 0.17~μ m 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 gate-length (L_ g)of0.17~μ mand source–drain spacing (L_ sd)of3.5~μ mexhibited 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 atV_ ds= 5V andI_ ds= 140mA/mm, which is the lowest noise characteristics ever reported for the GaN-based T-shaped gate HEMTs with gate length larger than0.1~μ m. 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.