Process for producing compound semiconductor using an amorphous nucleation site

A process for producing a compound semiconductor, which comprises applying a crystal forming treatment on a substrate having a free surface comprising a non-nucleation surface (S.sub.NDS) with a smaller nucleation density and an amorphous nucleation surface (S.sub.NDL) arranged adjacent thereto having a sufficiently small area so as to form a single nucleus from which a single crystal is grown and a larger nucleation density (ND.sub.L) than the nucleation density (ND.sub.S) of said nonnucleation surface (S.sub.NDS) so as to form only a single nucleus from which a single crystal is grown, by exposing the substrate to either of the gas phases:

• (a) gas phase (a) containing a starting material (II) for feeding the group II atoms of the periodic table and a starting material (VI) for feeding the group VI atoms of the periodic table;
• and
• (b) gas phase (b) containing a starting material (III) for feeding the group III atoms of the periodic table and a starting material (V) for feeding the group V atoms of the periodic table, thereby forming a single nucleus on said nucleation surface (S.sub.NDL) and permitting a monocrystal of the compound semiconductor to grow only from said single nucleus, characterized in that a semiconductor junction is formed in said monocrystal by feeding a starting material (Dn) for feeding a dopant for controlling to a first electroconduction type and a starting material (Dp) for feeding a dopant for controlling to a second electroconduction type opposite to said first electroconduction type with change-over to one another into said gas phase, during said crystal forming treatment.