Patent ID: 8243139

Claim:
An image pickup device comprising a two-dimensional array of pixels that are semiconductor light-receiving elements made of group III-V semiconductors formed on an InP substrate, the image pickup device being configured to capture an image of an object by receiving light in a near-infrared region reflected by the object, wherein each of the semiconductor light-receiving elements includes a light-receiving layer that is formed on the InP substrate and has a multi-quantum well structure composed of group III-V semiconductors; and a diffusion concentration distribution control layer made of group III-V semiconductors is disposed in contact with the light-receiving layer on a side of the light-receiving layer so as to be opposite the side adjacent to the InP substrate, the light-receiving layer has a band gap wavelength of 1.65 to 3 μm, the diffusion concentration distribution control layer has a lower band gap energy than InP, a pn junction is formed for each of the pixels by selective diffusion of an impurity element, the impurity in the light-receiving layer has a concentration of 5×10 16 /cm 3 or less, the diffusion concentration distribution control layer has an n-type impurity concentration of 2×10 15 /cm 3 or less before the diffusion, and the diffusion concentration distribution control layer having a portion adjacent to the light-receiving layer, the portion having a low impurity concentration.