LAMINATED BODY AND THE METHOD FOR PRODUCTION THEREOF

摘要

Disclosed is a self-supported Al-based group III nitride single crystal substrate. A base substrate is provided. The base substrate is formed of a single crystal of an inorganic material, for example, sapphire, that is not substantially decomposed at 800°C in an inert gas and, upon contact with a reducing gas such as a hydrogen gas at 800 to 1600°C, is decomposed to produce a volatile material. A thin film layer of an Al-based group III nitride single crystal having a thickness of 3 to 200 nm is formed on the base substrate. Thereafter, the laminated substrate is heat treated at 800 to 1600°C in a reducing gas atmosphere containing an ammonia gas to form voids at the interface of the base substrate and the thin film layer of the Al-based group III nitride single crystal in the laminated substrate. Next, a thick film of a group III nitride single crystal is formed on the thin film layer of the Al-based group III nitride single crystal, followed by separation of the formed film. Thus, a self-supported Al-based group III nitride single crystal substrate is provided that is a self-supported substrate of a single crystal of a group III nitride such as AlN which is suitable for use in the formation of semiconductor elements such as ultraviolet light emitting elements and has a large radius of curvature in a crystal plane.