Depletion-mode pseudomorphic In0.22Ga0.78As-channel MOSFETs with InAlP native oxide gate dielectric for RF applications

Pseudomorphic high electron-mobility transistors (pHEMTs) have demonstrated excellent high-speed, power and noise performance, and have been widely used in microwave and millimeter-wave circuits, as well as wireless and optoelectronic applications. Replacing the Schottky gate contacts in pHEMTs with insulating metal-oxide-semiconductor structures (pMOSFETs) can result in increased allowable gate voltage swing, while at the same time suppressing gate current due to the higher effective gate potential barrier. Here we present the first pseudomorpic In_0.22Ga_0.78As-channel MOSFETs with InAlP native oxide gate dielectric operating in depletion mode with significant performance enhancement compared to prior GaAs-channel MOSFETs with same gate dielectric, indicating clear promise of such devices for future RF applications.