Patent ID: 7625784

Claim:
A method for manufacturing a semiconductor device, comprising: forming a buffer layer made of single-crystalline silicon on a semiconductor substrate including a first region, the first region being arranged at a predetermined interval for providing a silicon on insulator (SOI) structure; after forming the buffer layer, forming a first semiconductor layer on the buffer layer; forming a second semiconductor on the first semiconductor layer; removing the first semiconductor layer, the second semiconductor layer, and the buffer layer from a second region, the second region being adjacent to the first region via one line and disposed singly to each of the first region, so as to form a recess for a support, the recess exposing the semiconductor substrate; forming a support precursor layer made of an insulating material on a region including at least the first region and the second region on the semiconductor substrate; etching and removing the support precursor layer except for a part thereof corresponding to the first region and corresponding to a part, the part including at least the one line, of a bottom part of the recess so as to form a support coupling the recess and the second semiconductor layer; etching a part of the first semiconductor layer and the second semiconductor layer by using the support as a mask to expose a first side section of the first semiconductor layer and the second semiconductor layer except for a second side section adjacent to the second region; etching and removing the first semiconductor layer selectively to the second semiconductor layer and the semiconductor substrate so as to form a cavity under the second semiconductor layer, wherein the cavity is formed between the second semiconductor layer and the buffer layer, the second semiconductor layer being an upper layer of the cavity and the buffer layer being a lower layer of the cavity; thermally oxidizing the second semiconductor layer and the buffer layer so as to form a buried insulating layer composed of a semiconductor oxide film in the cavity; and removing the support at least from the first region so as to expose the second semiconductor layer.