Patent ID: 8022449

Claim:
A photodiode array including a plurality of photodiodes that are arrayed in an epitaxial multilayer including an absorption layer composed of a Group III-V compound semiconductor, the epitaxial multilayer being grown on an InP substrate or a buffer layer disposed on the InP substrate, the photodiode array comprising: a first conductivity type region formed in each of the photodiodes by selective diffusion from the top surface side of the epitaxial multilayer; a first conductive-side electrode provided on the first conductivity type region; and a second conductive-side electrode provided for the plurality of photodiodes in common, wherein the InP substrate or the buffer layer has a non-growth part on which the epitaxial multilayer is not grown, the non-growth part being disposed at the periphery of the photodiode array, the second conductive-side electrode is connected to the non-growth part of the InP substrate or the buffer layer and extends to the top surface side of the epitaxial multilayer, a wall surface of an edge of the epitaxial multilayer at the second conductive-side electrode side is a smooth surface, a lattice defect density in a portion of the edge of the epitaxial multilayer is higher than a lattice defect density in the inside of the epitaxial multilayer, and a surface of the non-growth part of the InP substrate or the buffer layer is a flat surface continuous from the side at which the epitaxial multilayer is disposed.