Patent ID: 7893515

Claim:
A photodetector integrated chip comprising: a semiconductor photo receiving region on a silicon substrate having an upper light-receiving surface; an insulating layer on said surface of said silicon substrate; and an antireflection film comprising a laminated film, having a first insulating film formed on said upper light-receiving surface of said silicon substrate and a second insulating film having a refractive index different than that of said first insulating film formed on said first insulating film, is formed at least in a light-receiving area of said semiconductor photo receiving region, wherein, said first insulating film is comprised of a silicon oxide film formed by at least oxidizing silicon on the upper light-receiving surface of said semiconductor photo receiving region, said second insulating film is formed at a top of said semiconductor photo receiving region, the second insulating film having no insulation element formed thereon, and the thickness of the second insulating film is based on the thickness of the first insulating film and a wavelength of a light to be detected so as to minimize reflectance of the light at that wavelength, and the light to be detected has a wavelength of less than 500 nm.