High Microwave-Noise Performance of AlGaN/GaN MISHEMTs on Silicon With Al₂O₃ 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) Al2O3as gate insulator. The ALD Al2O3/AlGaN/GaN MISHEMT with a 0.25- ¿m gate length shows excellent microwave small signal and noise performance. A high current-gain cutoff frequencyfTof 40 GHz and maximum oscillation frequencyfmaxof 76 GHz were achieved. At 10 GHz, the device exhibits low minimum-noise figure (NFmin) 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 Al2O3gate insulator on high-resistivity Si substrate is suitable for microwave low-noise applications.