A method of manufacturing a semiconductor device may include forming a first n− type epitaxial layer by performing a first epitaxial growth on a first surface of an n+ type silicon carbide substrate, forming a photosensitive layer pattern on the first n− type epitaxial layer, etching the first n− type epitaxial layer by using the photosensitive layer pattern as a mask to form a first trench, forming a buffer layer on the first n− type epitaxial layer after the photosensitive layer pattern may be removed, etching the buffer layer to form a trench passivation layer in the first trench, forming an n− type epitaxial layer by performing a second epitaxial growth on the first n− type epitaxial layer, and forming a p type epitaxial layer by performing a third epitaxial growth on the n− type epitaxial layer other than the portion on which the trench passivation layer may be formed.