Soi substrate and process for preparing the same, and semiconductor device and process for preparing the same

Abstract

When producing an SOS substrate by growing a silicon layer on a sapphire substrate, or when producing an SOI substrate by depositing an oxide layer or a fluoride layer, as an intermediate layer, on a silicon substrate, and growing a silicon layer on the deposited layer, (A) after growth of the silicon layer, heat treatment is performed in an oxidizing atmosphere to oxidize a part of a surface side of the silicon layer, and the resulting silicon oxide layer is removed by etching with hydrofluoric acid. (B) With this silicon layer as a seed layer, a silicon layer is regrown homoepitaxially thereon.