Patent ID: 8390090

Claim:
A semiconductor device comprising: a transistor; and a light receiving element monolithically integrated with the transistor, wherein the light receiving element includes a p-type semiconductor layer, an n-type epitaxial layer formed on the p-type semiconductor layer, and an n-type diffusion layer formed on the n-type epitaxial layer, an n-type impurity concentration of the n-type diffusion layer is 3×10 18 cm −3 or less at a depth of 0.12 μm or more below a surface of the n-type diffusion layer, 1×10 16 cm −3 or more at a depth of 0.4 μm or less below the surface, and 1×10 16 cm −3 or less at a depth of 0.8 μm or more below the surface, and an interface between the p-type semiconductor layer and the n-type epitaxial layer is located at a depth of 0.9 μm to 1.5 μm below the surface.