Patent ID: 7910449

Claim:
A method of manufacturing a semiconductor device, comprising the steps of: preparing a one-conductivity-type semiconductor substrate, and then forming a first opposite-conductivity-type epitaxial layer on the semiconductor substrate; forming a second opposite-conductivity-type epitaxial layer on the first epitaxial layer after implanting ions of an impurity for forming a first one-conductivity-type buried diffusion layer into the first epitaxial layer; and forming an isolation region by firstly implanting ions of an impurity for forming a second one-conductivity-type buried diffusion layer from a surface of the second epitaxial layer, then continuously implanting ions of an impurity for forming a one-conductivity-type diffusion layer, and finally performing thermal diffusion, so as to connect the first one-conductivity-type buried diffusion layer, the second one-conductivity-type buried diffusion layer and the one-conductivity-type diffusion layer with one another.