Boron phosphide-based semiconductor device, production method thereof, light-emitting diode and boron phosphide-based semiconductor layer

A boron phosphide-based semiconductor device comprising:

• a silicon single crystal substrate (11);
• a boron phosphide-based polycrystalline layer formed on a {111} surface of said substrate;
• and
• a group III-V compound semiconductor layer stacked on said boron phosphide-based polycrystalline layer to form a hetero junction on the boron phosphide-based polycrystalline layer;
• wherein the boron phosphide-based polycrystalline layer is composed of an aggregate of a plurality of triangular pyramidal or truncated triangular pyramidal single crystal entities (13);
• each of said entities having a {111} bottom face (13a) that is parallel to said {111} surface of the substrate, having {111} side faces (15) and having a twinning interface that forms an angle of 60° relative to a <110> direction of said substrate;
• and
• wherein the group III-V compound semiconductor layer is composed of crystal planes arrayed at an interval agreeing with a lattice spacing of crystal planes intersecting with surfaces of the single crystal entities (13).