Patent ID: 8822316

Claim:
A manufacturing method of a semiconductor device, the method comprising: preparing a semiconductor substrate having a first conductive type layer; forming an insulator layer on the semiconductor substrate, the insulator layer including a second opening of a second size; forming a silicon oxide film on the semiconductor substrate in an area corresponding to the second opening; forming a resist pattern on the silicon oxide film and the insulator layer, the resist pattern including a first opening of a first size smaller than the second size; doping a first conductive type impurity through the silicon oxide film into the first conductive type layer so as to form a first diffusion region which has an area corresponding to the first size; removing the resist pattern such that the insulator layer and the silicon oxide film remain on the semiconductor substrate; and doping a second type impurity through the silicon oxide film into the first conductive type layer so as to form a second diffusion region which has an area corresponding to the second size larger than an area of the first diffusion region and overlaps the first diffusion region, wherein a part of the first diffusion region is inverted from the first conductive type to the second conductive type by doping the second type impurity so as to form a PN junction.