METHOD AND DEVICE FOR MANUFACTURING SEMICONDUCTOR SUBSTRATE

摘要

The average depth and concentration of oxygen by a series of oxygen ion implantation are changed continuously or stepwise for every implantation in such a way that there is one maximum in the oxygen atom concentration distribution in the depth direction, and the concentration is constant at the same depth. The maximum oxygen atom concentration is preferably 1.0 to 2.25 x 10<22> cm<-3>. The total dosage is equal to the product of the thickness of a desired buried oxide film by a value 48 x 10<22>. After the ion implantation, heat treatment at above 1,300 DEG C is preferably done to form the buried oxide film.