Semiconductor device provided with photodiode, manufacturing method thereof, and optical disc device

摘要

A semiconductor device includes: a P-type semiconductor substrate; a first P-type semiconductor layer formed on the P-type semiconductor substrate; a second P-type semiconductor layer formed on the first P-type semiconductor layer and having a lower P-type impurity concentration than the first P-type semiconductor layer; an N-type semiconductor layer, which will form a cathode region, formed on the second P-type semiconductor layer; a first P-type diffusion layer formed by diffusing a P-type impurity in a partial region of the second P-type semiconductor layer; a second P-type diffusion layer formed by diffusing a P-type impurity in the second P-type semiconductor layer so as to be present adjacently beneath the first P-type diffusion layer at a lower P-type impurity concentration than the first P-type diffusion layer; and a photodiode formed in such a manner that the N-type semiconductor layer and the first P-type diffusion layer are isolated from each other.

主权项

1. A semiconductor device comprising:
a heavily doped P-type diffusion layer extending from a surface of a semiconductor substrate to a lightly doped P-type diffusion layer, an impurity concentration of a P-type in the heavily doped P-type diffusion layer being higher than an impurity concentration of the P-type in the lightly doped P-type diffusion layer; an N-type semiconductor layer extending from said surface of the semiconductor substrate to a lightly doped P-type semiconductor layer, said impurity concentration of the P-type in the heavily doped P-type diffusion layer being higher than an impurity concentration of the P-type in the lightly doped P-type semiconductor layer; a collector diffusion layer region extending from said surface of the semiconductor substrate to said lightly doped P-type diffusion layer, an N-type impurity being within said collector diffusion layer region, wherein a portion of the lightly doped P-type diffusion layer is between said heavily doped P-type diffusion layer and said collector diffusion layer region, said portion of the lightly doped P-type diffusion layer touching said surface of the semiconductor substrate, wherein said lightly doped P-type semiconductor layer touches said heavily doped P-type diffusion layer and said lightly doped P-type diffusion layer, a portion of the lightly doped P-type semiconductor layer physically separating said N-type semiconductor layer from said heavily doped P-type diffusion layer.