Microwave performance of a quarter-micrometer gate low-noise pseudomorphic InGaAs/AlGaAs modulation-doped field effect transistor

Excellent dc and millimeter-wave performance is reported in In0.15Ga0.85As/Al0.15Ga0.85As pseudomorphic modulation-doped field effect transistors (MODFET's) with 0.25-micron-length gates. Extrinsic transconductances as high as 495 mS/mm at 300 K and unprecedented power performance in the 60-GHz range were observed. Although not yet optimized, excellent low noise characteristics, 0.9 dB, with an associated gain of 10.4 dB at 18 GHz, and a noise figure of 2.4 dB with an associated gain of 4.4 dB at 62 GHz were obtained. This is the best noise performance ever reported for a MODFET in this frequency range. These results clearly demonstrate the superiority of pseudomorphic MODFET structures in high-frequency applications.