Millimeter-wave AlGaAs/InGaAs/GaAs quantum well power MISFET

State-of-the-art millimeter-wave power transistors using quantum-well MISFET structures have been developed. Single- and double-quantum-well devices have been built, with maximum currents of 700 mA/mm for the single-well and 900 mA/mm for the double-well devices. The single-well devices delivered a power density of 0.76 W/mm with 3.6-dB gain and 19% efficiency at 60 GHz. The double well MISFETs had a power density of 0.96 W/mm with 3-dB gain and 24% power-added efficiency at 55 GHz. The highest power-added efficiency was 31% with 0.68 W/mm power density and 4-dB gain. The power performance of the double-well device was better than that of the single-well device.<
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