Patent ID: 7453135

Claim:
A semiconductor device comprising: an SOI substrate including a substrate serving as a base, a buried oxide film provided on said substrate, and an SOI layer provided on said buried oxide film; plural first isolation films provided in a main surface of said SOI layer in a first region defined on said SOI substrate, with a portion of said SOI layer interposed therebetween; and plural resistive elements provided on said plural first isolation films in said first region, respectively; wherein at least a portion of each of said plural first isolation films passes through said SOI layer and reaches said buried oxide film to include a full-trench isolation structure; wherein each of said plural first isolation films includes a hybrid-trench isolation structure in which a central portion includes said full-trench isolation structure and each of opposite side portions is located on said SOI layer to include a partial-trench isolation structure, in section; wherein said SOI layer is an impurity layer of a first conductivity type, further comprising: a MOS transistor provided in an element forming region of said SOI layer; and a partial isolation region provided in said SOI layer; wherein said partial isolation region includes partial isolation films formed in an upper layer of said SOI layer and a semiconductor region located under partial isolation films of the first conductivity type which is a part of said SOI layer in a lower layer, said MOS transistor includes second conductivity type source/drain layers each selectively formed in said SOI layer, a gate electrode provided over a region of said SOI layer positioned between said source/drain layers, with a gate oxide film lying between said electrode and said region, and a channel region of the first conductivity type provided on an upper layer of said SOI layer between said source/drain layers, said channel region is electrically connected to a body-potential fixing region of the first conductivity type, with said semiconductor region located under partial isolation films lying between said channel region and said body-potential region.