Patent ID: 7955984
Filing Date: 2011-06-07
Classification: H01L

Abstract:
1. A method for manufacturing a nitride semiconductor device comprising: epitaxially growing a lower nitride semiconductor layer and an upper nitride semiconductor layer, over a substrate; etching said upper nitride semiconductor layer at a source contact region and a drain contact region; forming a source electrode at said source contact region and a drain electrode at said drain contact region, respectively in ohmic contact with said lower nitride semiconductor layer; forming an insulating protective film over said upper nitride semiconductor layer covering said source electrode and said drain electrode; etching said insulating protective film by using a resist mask to form an opening portion, including performing first anisotropic etching to form an opening in the insulating protective film reaching an intermediate depth, after performing the first anisotropic etching, rounding resist corners at an opening edge by curing resist, and, after rounding the resist corners at the opening edge, performing second anisotropic etching, so that the insulating protective film has a steeply rising sidewall at an opening edge to a partial thickness of a total thickness of said insulating protective film and reaching a total thickness portion via a transition portion which has monotonously increasing thickness with a distance from the opening edge; and forming a gate electrode over said upper nitride semiconductor layer in said opening and extending on said insulating protective film to portions of increased thickness thicker than said partial thickness.