Patent ID: 7981704

Claim:
A method for manufacturing a semiconductor optical device, comprising: sequentially laminating a first semiconductor layer of a first conductivity type, an active layer, a second semiconductor layer of a gallium nitride-based compound semiconductor material having a second conductivity type, and a metal cap layer on a semiconductor substrate, to form a semiconductor laminated structure; applying a resist onto a surface of the semiconductor laminated structure, and forming a first resist pattern, with a stripe-shaped resist film portion having a width corresponding to a waveguide ridge, using photolithography; etching and removing the metal cap layer, using the first resist pattern as a mask, thereby exposing the second semiconductor layer; removing a part of the second semiconductor layer by dry etching, using the first resist pattern as a mask, thereby forming a dent, leaving a part of the second semiconductor layer on a bottom of the dent, and thereby forming the waveguide ridge; forming an insulating film on the surface of the semiconductor laminated structure containing the dent, and the waveguide ridge having the metal cap layer on an uppermost surface, after removing the first resist pattern; forming a second resist pattern, the second resist pattern exposing an upper surface of the insulating film on top of the waveguide ridge, and burying the insulating film in the dent adjoining the waveguide ridge with a resist film having a surface farther from the substrate than the surface of the second semiconductor layer of the waveguide ridge and closer to the upper substrate than the surface of the insulating film on the top of the waveguide ridge; removing the insulating film by dry etching, using the second resist pattern as a mask, thereby exposing the metal cap layer of the waveguide ridge; removing the metal cap layer by wet etching, thereby exposing the second semiconductor layer; and forming an electrode layer on the surface of the second semiconductor layer of the waveguide ridge that is exposed.