A method of manufacturing a semiconductor device wherein a pair of grooves having different depths are formed in a surface of a semiconductor substrate, an epitaxial layer of one conductivity type is grown to a depth enough to fill a shallower one of the grooves, and an epitaxial layer of the opposite conductivity type is further grown to a depth enough to fill a deeper one of the grooves, followed by the step of etching the entire surface to expose the surface of said semiconductor substrate and to leave in each groove an epitaxial layer of mutually different conductivity type and having the same depth and width. A semiconductor device as manufactured by the above method.