A substrate with a second semiconductor layer and a second mask film formed thereon
is subjected to a heat treatment in an oxidizing atmosphere. Thus, second oxidized
regions are formed through oxidization of the second semiconductor layer in regions
of the second semiconductor layer that are not covered by the second mask film.
At the same time, a second base layer is formed in each region that is interposed
by the second oxidized regions. Then, the second mask film is removed, and a third
semiconductor layer is selectively grown on the surface of the second base layer
that is exposed between the second oxidized regions so as to cover the second oxidized
regions, after which the first oxidized regions and the second oxidized regions
covering the entire upper surface of the substrate are removed.