We propose and fabricate an A1GaN/GaN high electron mobility transistor (HEMT) on sapphire substrate using a new kind of electron beam (EB) lithography layout for the T-gate. Using this new layout,we can change th...We propose and fabricate an A1GaN/GaN high electron mobility transistor (HEMT) on sapphire substrate using a new kind of electron beam (EB) lithography layout for the T-gate. Using this new layout,we can change the aspect ratio (ratio of top gate dimension to gate length) and modify the shape of the T-gate freely. Therefore, we obtain a 0.18μm gate-length AlGaN/GaN HEMT with a unity current gain cutoff frequency (fT) of 65GHz. The aspect ratio of the T-gate is 10. These single finger devices also exhibit a peak extrinsic transconductance of 287mS/mm and a maximum drain current as high as 980mA/mm.展开更多
A self-aligned InP/GalnAs single heterojunction bipolar transistor(HBT) is investigated using a novel T-shaped emitter. A U-shaped emitter layout,selective wet etching,laterally etched undercut, and an air-bridge ar...A self-aligned InP/GalnAs single heterojunction bipolar transistor(HBT) is investigated using a novel T-shaped emitter. A U-shaped emitter layout,selective wet etching,laterally etched undercut, and an air-bridge are applied in this process. The device, which has a 2μm×12μm U-shaped emitter area,demonstrates a common-emitter DC current gain of 170,an offset voltage of 0.2V,a knee voltage of 0.5V, and an open-base breakdown voltage of over 2V. The HBT exhibits good microwave performance with a current gain cutoff frequency of 85GHz and a maximum oscillation frequency of 72GHz, These results indicate that these InP/InGaAs SHBTs are suitable for low-voltage,low-power,and high-frequency applications.展开更多
文摘We propose and fabricate an A1GaN/GaN high electron mobility transistor (HEMT) on sapphire substrate using a new kind of electron beam (EB) lithography layout for the T-gate. Using this new layout,we can change the aspect ratio (ratio of top gate dimension to gate length) and modify the shape of the T-gate freely. Therefore, we obtain a 0.18μm gate-length AlGaN/GaN HEMT with a unity current gain cutoff frequency (fT) of 65GHz. The aspect ratio of the T-gate is 10. These single finger devices also exhibit a peak extrinsic transconductance of 287mS/mm and a maximum drain current as high as 980mA/mm.
文摘A self-aligned InP/GalnAs single heterojunction bipolar transistor(HBT) is investigated using a novel T-shaped emitter. A U-shaped emitter layout,selective wet etching,laterally etched undercut, and an air-bridge are applied in this process. The device, which has a 2μm×12μm U-shaped emitter area,demonstrates a common-emitter DC current gain of 170,an offset voltage of 0.2V,a knee voltage of 0.5V, and an open-base breakdown voltage of over 2V. The HBT exhibits good microwave performance with a current gain cutoff frequency of 85GHz and a maximum oscillation frequency of 72GHz, These results indicate that these InP/InGaAs SHBTs are suitable for low-voltage,low-power,and high-frequency applications.