Microwave performance of InAlAs/InGaAs/InP MODFET's

Modulation-doped InAlAs/InGaAs/InP structures were grown by molecular beam epitaxy (MBE) and fabricated into FET's with excellent RF gain performance. The intrinsic transconductance was about 400 mS/mm at 300 K. Current gain cutoff frequencies of up to 26.5 GHz were obtained in 1-µm gate devices. Extremely small S
12
and large S
21
led to a very large
f_{\max}
of 62 GHz. These results represent the best reported figures for 1-µm devices in this material system and slightly better than those obtained in recently developed pseudomorphic modulation-doped field effect transistors (MODFET's).