PURPOSE: To reduce the manhours for manufacturing a thick semiconductor crystal layer by a method wherein, in order to form an aperture part insulating film, the insulating film once formed on the surface of an epitaxially grown semiconductor crystal layer is removed to be epitaxially grown again on the whole surface.

CONSTITUTION: An aperture part insulating film 8 is formed on a semiconductor substrate 1 exposed in an aperture part 7 to be connected to an insulating film 2. That is, when the whole body is heat-treated at 1000°C for 70 minutes, silicon on the semiconductor substrate 1 is oxidized to form an oxide film in almost the same thickness as that of the insulating film 2 thereby enabling an aperture part insulating film 8 to be detected. At this time, the surface of a silicon carbide crystal growth layer as well as the side of the second aperture part 7 are oxidized so as to form a crystal deposited oxide film 9. Next, the crystal growth layer oxide film 9 is removed and then a semiconductor crystal layer 11 is epitaxially grown. Through these procedures, the semiconductor crystal layer 11 can be formed on the insulating film 2 without requiring any complicated steps such as the formation and removal, etc., of an oxidation preventive film at all.