Silicon on insulator (SOI) devices and methods for fabricating the same are provided. An exemplary embodiment of a SOI device comprises a substrate. A first insulating layer is formed over the substrate. A plurality of semiconductor islands is formed over the first insulating layer, wherein the semiconductor islands are isolated from each other. A second insulating layer is formed over the first insulating layer, protruding over the semiconductor islands and surrounding thereof. At least one recess is formed in a portion of the second insulating layer adjacent to a pair of the semiconductor islands. A first dielectric layer is formed on a portion of each of the semiconductor islands. A conductive layer is formed over the first dielectric layer and over the second insulating layer exposed by the recess. A pair of source/drain regions is oppositely formed in portions of each of the semiconductor islands not covered by the first dielectric layer and the conductive layer.