Method of manufacturing a semiconductor device, method of manufacturing a SOI device, semiconductor device, and SOI device

According to one embodiment of the present invention, a SOI device includes a first composite structure including a substrate layer, a substrate isolation layer being disposed on or above the substrate layer, a buried layer being disposed on or above the substrate isolation layer, and a semiconductor layer being disposed on or above the buried layer; a trench structure being formed within the first composite structure; and a second composite structure provided on the side walls of the trench structure, wherein the second composite structure includes a first isolation layer covering the part of the side walls formed by the semiconductor layer and formed by an upper part of the buried layer; and a contact layer covering the isolation layer and the part of the side walls formed by a lower part of the buried layer.