High Microwave-Noise Performance of AlGaN/GaN MISHEMTs on Silicon With $\hbox{Al}_{2}\hbox{O}_{3}$ Gate Insulator Grown by ALD

High microwave-noise performance is realized in AlGaN/GaN metal-insulator semiconductor high-electron mobility transistors (MISHEMTs) on high-resistivity silicon substrate using atomic-layer-deposited (ALD) Al 2 O 3 as gate insulator. The ALD Al 2 O 3 /AlGaN/GaN MISHEMT with a 0.25- ?m gate length shows excellent microwave small signal and noise performance. A high current-gain cutoff frequency fT of 40 GHz and maximum oscillation frequency f max of 76 GHz were achieved. At 10 GHz, the device exhibits low minimum-noise figure (NF min ) of 1.0 dB together with high associate gain ( Ga ) of 10.5 dB and low equivalent noise resistance ( Rn ) of 29.2 ?. This is believed to be the first report of a 0.25-?m gate-length GaN MISHEMT on silicon with such microwave-noise performance. These results indicate that the AlGaN/GaN MISHEMT with ALD Al 2 O 3 gate insulator on high-resistivity Si substrate is suitable for microwave low-noise applications.