FABRICATION METHOD OF COMPOUND SEMICONDUCTOR DEVICE HAVING GATE ELECTRODE OF STAIRS TYPE

摘要

PURPOSE: A compound semiconductor device having a gate electrode of a stairs type is provided so as to improve a heat-resistibility and an insulating ability by using a two-steps etching process of a heat-resistible metal thin-layer and an insulating layer. CONSTITUTION: A fabrication method of the compound semiconductor device having the gate electrode of the stairs type contains the following processes: a process to compose an etch-stop layer, an ohmic layer, an insulation layer, and a heat-resistibility metal layer orderly on the compound semiconductor epitaxial substrate having several epitaxial layers; a process to form a gate insulation layer pattern of the stairs shape by etching the above heat-resistibility metal layer and insulation layer through the two-steps etching process; a process to form a gate recess pattern of T type pillar by etching the above ohmic contact layer and etch-stop layer through using a process of a two-steps gate recess to use a photo-resist pattern as a mask; a process to form the gate electrode of the stairs shape by lifting off the above photo-resist pattern, after evaporating in vacuum a gate metal on the above gate recess pattern; and a process to form a self-aligned source and drain electrode.