PURPOSE: To form a single crystal semiconductor film having a desired conductivity type, which is isolated from a semiconductor substrate with an insulating film, readily, by forming an Al film, to which Si is added, on the Si substrate, and growing the Si in the Al film by solid phase epitaxy on the Si substrate by heat treatment.

CONSTITUTION: A groove 2 is formed in a semiconductor substrate 1. An insulating film 3 is formed on the surface of the (n) semiconductor substrate at least at the inside of the groove so that the semiconductor substrate 1 is exposed on one side wall 2a of the groove 2. A metal film 4 is formed on the surface of the semiconductor substrate, which is exposed at the side wall of the groove 2. Then, a polycrystalline Si semiconductor film 5 is formed on the insulating film 3 and the metal film 4. Heating is performed at a specified temperature cycle. Thus the solid phase epitaxial growth of a single crystal semiconductor film, which includes metal atoms forming the metal film 4, is performed on the insulating film 3. Then, the single crystal semiconductor film having the desired conductivity type is readily formed under the state the film is isolated from the semiconductor substrate by the insulating film.