Field effect transistor using compound semiconductor

Abstract

A compound semiconductor device such as HEMTs (High Electron Mobility Transistors), metal semiconductor field effect transistors, and the like includes a compound semiconductor substrate having an active region, an insulating film provided over the semiconductor substrate, source and drain electrodes provided on the active region, and a gate electrode located between the source and drain electrodes. In the structure, the gate electrode has a lower electrode portion for providing a Schottky barrier contact with the active region through an opening of the insulating film, and an upper electrode portion provided on the insulating film to extend toward only the drain electrode.