Patent ID: 7768090

Claim:
A semiconductor photodetector device, comprising: a light receiving element region including: a light receiving operation section converting incident light to an electric signal and a current amplifying operation section amplifying the electric signal, wherein the light receiving operation section includes: a semiconductor layer of a first conductivity type formed on a first conductivity type semiconductor substrate; a first semiconductor region of a second conductivity type formed on the semiconductor layer; a second semiconductor region of the first conductivity type formed in the semiconductor layer; and a first isolation insulating layer separating the first semiconductor region from the second semiconductor region; and the current amplifying operation section amplifying the electric signal includes: the second semiconductor region; a third semiconductor region of the second conductivity type formed in the semiconductor substrate separately from the second semiconductor region; a fourth semiconductor region of the second conductivity type formed on the third semiconductor region; and a second isolation insulating layer separating the second semiconductor region from the fourth semiconductor region, wherein the first semiconductor region and the first isolation insulating layer are formed to be separated from each other, and the first isolation insulating layer has a bottom face located shallower than a bottom face of the semiconductor layer.