Patent ID: 8916931

Claim:
A semiconductor device comprising: a semiconductor substrate of a first general conductivity type; an epitaxial layer of a second general conductivity type formed on the semiconductor substrate; a buried layer of the second general conductivity type formed in a boundary region between the semiconductor substrate and the epitaxial layer; a drift layer of the second general conductivity type formed in a surface portion of the epitaxial layer; an element isolation layer of the first general conductivity type formed in the epitaxial layer so as to surround the drift layer; a drain layer of the second general conductivity type formed in a surface portion of the drift layer and connected to a drain electrode of the semiconductor device; a drain isolation layer of the first general conductivity type formed in the epitaxial layer so as to surround the drift layer and the drain layer; a hole collection layer of the first general conductivity type connected to a collector electrode of the semiconductor device and formed in a surface portion of the epitaxial layer that is between the drain isolation layer and the element isolation layer; a guard ring layer of the second general conductivity type formed in a surface portion of the epitaxial layer so as to be in direct contact with and surrounding an upper portion of the hole collection layer at a surface of the epitaxial layer, wherein the hole collection layer extends into the epitaxial layer below the guard ring layer, the element isolation layer surrounding the epitaxial layer containing the guard ring layer; a body layer of the first general conductivity type formed in a surface portion of the epitaxial layer; a source layer of the second general conductivity type formed in a surface portion of the body layer; a gate insulation film formed on a surface portion of the body layer; and a gate electrode of the semiconductor device formed on the gate insulation film.