Patent ID: 8178913

Claim:
A semiconductor device comprising: a semiconductor substrate; a first-conductivity-type region formed in an upper portion of the semiconductor substrate and having a first conductivity type; a second-conductivity-type region formed in the upper portion of the semiconductor substrate, in contact with the first-conductivity-type region, and having a second conductivity type that is different from the first conductivity type; a buried dielectric film provided immediately above the second-conductivity-type region, the buried dielectric film having a lower portion buried in the semiconductor substrate and an upper portion protruding from an upper surface of the semiconductor substrate, a lower surface of the buried dielectric film being at a level higher than a lower surface of the first-conductive-type region; and an element isolation film having a lower portion buried in the semiconductor substrate, having an upper portion protruding from the upper surface of the semiconductor substrate, and having a lower surface located below a lower surface of the buried dielectric film, wherein the second-conductivity-type region and the buried dielectric film are in contact with the first-conductivity-type region and isolate the first-conductivity-type region from a region that is on opposite side of the first-conductivity-type region across the second-conductivity-type region and is in contact with the second-conductivity-type region.