Semiconductor device and manufacturing method thereof

A manufacturing method of semiconductor device, comprising the steps of:

• (a) preparing a substrate;
• (b) forming a first semiconductor layer including an impurity of a first conductive type, over the substrate;
• (c) forming a first insulating film over the substrate;
• (d) forming a through part in the first insulating film by selectively removing the first insulating film;
• (e) forming a second semiconductor layer over the first semiconductor layer exposed within the through part, after the step (d);
• (f) forming a fourth semiconductor layer of a material different from that of the semiconductor layer, over the second semiconductor layer;
• (g) forming a third semiconductor layer within the second semiconductor layer, by introducing an impurity of a second conductive type opposite to the first conductive type into part of the second semiconductor layer;
• (h) forming a first interlayer insulating film over the first semiconductor layer and over the fourth semiconductor layer;
• (i) forming a first contact hole reaching the fourth semiconductor layer, in the first interlayer insulating film;
• (j) forming a first compound layer, which is a reaction product of a first metal and the material included in the fourth semiconductor layer, inside the first contact hole, in such a way that a reaction product of the first metal and the material included in the third semiconductor layer is not formed within the third semiconductor layer;
• and
• (k) forming a first plug inside the first contact hole, the first plug being electrically coupled to the third semiconductor layer through the first compound layer,
• wherein the first semiconductor layer, the second semiconductor layer, and the third semiconductor layer respectively configure part of the photoreceiver.