Patent ID: 7042059

Claim:
A method for manufacturing an optical semiconductor device having a photo detector section to receive light and generate a photocurrent and a circuit element section to process a signal based on the photocurrent from said photo detector section on a same semiconductor substrate, the method comprising: forming a first semiconductor layer of a first conductivity type on a surface of the semiconductor substrate; forming a second semiconductor layer of a second conductivity type on a surface of said first semiconductor layer; forming selectively diffused layers in said second semiconductor layer in said photo detector section and said circuit element section; depositing a first insulating film on said second semiconductor layer; exposing said second semiconductor layer in a light-receiving region which receives the light in said photo detector section; and forming an antireflection film on said second semiconductor layer in said light-receiving region, and forming a passivation film above said first insulating film, said antireflection film preventing a reflection of an incident light, said passivation film being made of a same material as a material of said antireflection film and covering said circuit element section, and said antireflection film being continuous with said passivation film.