Patent ID: 7834413

Claim:
A semiconductor photodetector in which a plurality of compound semiconductor layers are laminated, comprising: a structural body of layers including said plurality of compound semiconductor layers; a silicon oxide film provided on a light-incident surface side of said structural body of layers; and a glass substrate optically transparent to incident light, said glass substrate adhered onto said light-incident surface side of said structural body of layers, through said silicon oxide film, wherein said structural body of layers includes a high-concentration carrier layer of a first conductivity type, a light absorbing layer of the first conductivity type, and a cap layer of the first conductivity type that are laminated in that order from said light-incident surface side as said plurality of compound semiconductor layers, and wherein a photosensitive region of a second conductivity type is formed on at least said cap layer, and wherein said plurality of compound semiconductor layers is constituted by: a photosensitive portion shaped to a mesa-form, said photosensitive portion including a part of said cap layer that includes a periphery of said photosensitive region, a part of said light absorbing layer adjacent to the part of said cap layer, and a part of said high-concentration carrier layer adjacent to the part of said light absorbing layer; a first pad electrode positioning portion being adjacent to said photosensitive portion and shaped to a mesa-form, said first pad electrode positioning portion including a part of said cap layer, a part of said light absorbing layer, and a part of said high-concentration carrier layer; and a second pad electrode positioning portion being shaped to a mesa-form and provided so as to sandwich said photosensitive portion together with said first pad electrode positioning portion, said second pad electrode positioning portion including a part of said cap layer, a part of said light absorbing layer, and a part of said high-concentration carrier layer, wherein said photosensitive portion has a depression that reaches from the part of said cap layer to said high-concentration carrier layer, and wherein said semiconductor photodetector further comprises: a first pad electrode arranged on said first pad electrode positioning portion; a first wiring electrode electrically connecting said first pad electrode and said photosensitive region, said first wiring electrode having a part formed so as to extend along side surfaces of said photosensitive portion and said first pad electrode positioning portion; a second pad electrode arranged on said second pad electrode positioning portion; and a second wiring electrode electrically connecting said second pad electrode and said high-concentration carrier layer of said photosensitive portion, said second wiring electrode having a part formed so as to extend along side surfaces of said depression, said photosensitive portion, and said second pad electrode positioning portion.