Process for producing crystal article

Claim 1

A process for producing a Si crystal article on a glass substrate comprising the steps of: forming a silicon nitride film on the glass substrate; forming a film comprising SiO 2 on the silicon nitride film; selectively etching the film comprising SiO 2 to form a concavity surrounded by side walls of the remaining portion of the film comprising SiO 2 ; thermally oxidizing the silicon nitride film to form another film comprising SiO 2 on the surface of the silicon nitride film and to anneal the side walls, thereby densifying the side walls; forming an opening in said another film comprising SiO 2 so as to expose a portion of the silicon nitride film in an area sufficiently small such that only a single nucleus from which a Si single-crystal is grown is formed in said opening; applying vapor deposition to form said Si single-crystal in said concavity from the single nucleus on the silicon nitride film; and flattening the surface of the Si single-crystal by removing a part thereof.