Surface smoothing method and method of forming SOI substrate using the surface smoothing method

Abstract

This invention relates to a surface smoothing method for smoothing the surface of a semiconductor film and insulating film, etc, and a method of forming and SOI substrate by using this surface smoothing method. In this surface smoothing method, the surface of a semiconductor film or an insulating film formed on a substrate is irradiated with an ion beam at an incident angle of about 85.degree. or more, to the normal direction of the surface, while revolving the substrate, whereby the surface is smoothed easily without any contamination thereof or physical deformation of the surface layer. When this surface smoothing method is used in forming an SOI substrate used for a semiconductor three-dimensional circuit element, a single crystal insulating film is formed on a single crystal silicon substrate, and, after annealing, the surface of the insulating film is smoothed by this surface smoothing method and a single crystal silicon film is formed on the smoothed surface thereof, whereby the crystallinity and the surface characteristics of the insulating film are improved and a better quality formed single crystal silicon film is obtained, leading to higher quality of the SOI substrate.

Dependencies are inferred from the claim text.