Patent attributes
A field effect transistor includes a GaN epitaxial substrate, a gate electrode formed on an electron channel layer of the substrate, and source and drain electrodes arranged spaced apart by a prescribed distance on opposite sides of the gate electrode. The source and drain electrodes are in ohmic contact with the substrate. At an upper portion of the gate electrode, a field plate is formed protruding like a visor to the side of drain electrode. Between the electron channel layer of the epitaxial substrate and the field plate, a dielectric film is formed. The dielectric film is partially removed at a region immediately below the field plate, to be flush with a terminal end surface of the field plate. The dielectric film extends from a lower end of the removed portion to the drain electrode, to be overlapped on the drain electrode.