GALLIUM OXIDE SINGLE CRYSTAL COMPOSITE, PROCESS FOR PRODUCING THE SAME, AND PROCESS FOR PRODUCING NITRIDE SEMICONDUCTOR FILM UTILIZING GALLIUM OXIDE SINGLE CRYSTAL COMPOSITE

摘要

A gallium oxide single crystal composite that at the crystal growth of, for example, a nitride semiconductor, enables production of a high-quality cubic crystal in which mixing of a hexagonal crystal is reduced to thereby realize dominant growth of a cubic crystal over hexagonal crystal, and that can be utilized as especially a substrate suitable for epitaxial growth of cubic GaN; a process for producing the same; and a process for producing a nitride semiconductor film. There is provided a gallium oxide single crystal composite, comprising a gallium oxide single crystal and, superimposed on a surface thereof, a gallium nitride layer of cubic gallium nitride. Further, there is provided a process for producing a gallium oxide single crystal composite, comprising subjecting a surface of gallium oxide single crystal to nitriding treatment by means of ECR plasma or RF plasma so as to form a gallium nitride layer of cubic gallium nitride on the surface of gallium oxide single crystal. Still further, there is provided a process for producing a nitride semiconductor film, comprising growing a nitride semiconductor film on the above-mentioned surface of gallium oxide single crystal composite according to the RF-MBE method.