Patent ID: 7960202

Claim:
A method for making a photodiode array, having a plurality of photodiodes formed on a semiconductor substrate, comprising the steps of: epitaxially growing a first semiconductor layer having the same conductive type as that of the semiconductor substrate on the semiconductor substrate; forming a plurality of second semiconductor layers having an opposite conductive type to that of the semiconductor substrate on the surface side of the first semiconductor layer; and forming crystal fused regions by adjusting converging points of laser lights to the insides of the first semiconductor layer and semiconductor substrate and by being irradiated by laser lights along spaces between the plurality of second semiconductor layers to fuse the first semiconductor layer and the semiconductor substrate, wherein a semiconductor material making up at least one of said photodiodes is Si, and wherein in the step of forming crystal fused regions, a laser light having a photon energy smaller than the band gap of the absorption of Si is irradiated with at least one of said adjusted converging points of the laser light to be inside of the semiconductor material and between the plurality of photodiodes, to form a crystal fused region.