A plurality of trenches are formed so as to reach a prescribed depth from the surface of an n-type epitaxial layer. A refractory metal carbide film, such as a TaC film is formed via sputtering on the surface of sections (mesa regions) of the n-type epitaxial layer interposed between the adjacent trenches. Sections of the TaC film on the inner walls of the trenches are removed via etching. While the surface of the mesa regions is covered by the TaC film, the inside of the trenches is filled with a p-type epitaxial layer that is grown by CVD, thereby forming a parallel pn structure. Then, sections of the p-type epitaxial layer protruding above the surface of the parallel pn structure and the TaC film above the surface of the mesa regions are ground until top surfaces of n-type regions and p-type regions of the parallel pn structure are exposed.