High-transconductance heterostructure Ga/sub 0.47/In/sub 0.53/As/InP metal-insulator-semiconductor field-effect transistors grown by chemical beam epitaxy

SiO/sub 2/ insulator is on top of an InP layer; current transport occurs, however, an in adjacent n-type Ga/sub 0.47/In/sub 0.53/As:Sn layer. A transconductance of g/sub m/=300 mS/mm is obtained from depletion-mode MISFETs with a gate length of 1.2 mu m. This MIS (metal-insulator-semiconductor) junction has a symmetric current-voltage characteristic and a low-leakage current of approximately 1 nA at +or-2 V. High-frequency S-parameter measurements performed b probing devices on the wafers yield a unity current gain frequency of F/sub t/=22.2 GHz and a maximum frequency of oscillation f/sub max/=27 GHz.>