Semiconductor device and method for manufacturing same

A method for manufacturing semiconductor device comprising:

• a step of selectively implanting an n type impurity into a front surface of a p type semiconductor substrate and thereafter forming a first n type epitaxial layer on the front surface of the p type semiconductor substrate to form an n type embedded layer that extends across a boundary between the p type semiconductor substrate and the first n type epitaxial layer;
• a step of selectively implanting a p type impurity into a front surface of the first n type epitaxial layer and thereafter forming a second n type epitaxial layer on the front surface of the first n type epitaxial layer to form a p type embedded layer between the first n type epitaxial layer and the second n type epitaxial layer;
• a step of forming, in a surface layer portion of the second n type epitaxial layer, a p type well layer that is disposed above the p type embedded layer;
• and
• a step of forming, in a surface layer portion of the p type well layer, an n type source contact region that is higher in impurity concentration than the second n type epitaxial layer and forming, in the surface layer portion of the second n type epitaxial layer, an n type drain contact region that is higher in impurity concentration than the second n type epitaxial layer.