Method of manufacturing an insulated-gate field-effect transistor

Abstract

An insulated-gate field-effect transistor is disclosed which is particularly suitable for forming high-frequency transistors for a common source circuit configuration. The field-effect transistor is obtained in a simple and reliable manner using the following steps: (a) forming on an insulating layer a gate layer having separate, parallel apertures; (b) doping said epitaxial layer via said apertures so as to form parallel islands from which at least a portion of the source fingers is to be provided; (c) providing an etch-resistant mask having smaller parallel apertures each of which overlies an area of an island; (d) etching away said areas and underlying parts of the epitaxial layer so as to form parallel V-shaped grooves which expose the substrate, extend longitudinally along the islands and are adjoined along opposite sides by remaining parts of said islands, and (e) providing within the apertures of the gate layer and over the walls of the grooves parallel metal fingers which extend longitudinally along said islands to short-circuit the remaining parts of said islands to the epitaxial layer and to the substrate. These remaining parts form source fingers of the transistor. At least part of the drain fingers may also be formed in step (b).