Patent ID: 8017996

Claim:
A semiconductor device, comprising: a high breakdown voltage semiconductor element including a switching element and a JFET element, wherein the high breakdown voltage semiconductor element includes a drift region of a first conductivity type formed at a surface of a first semiconductor substrate, a base region of a second conductivity type formed adjacent to the drift region at the surface of the first semiconductor substrate, a source region of a first conductivity type formed spaced apart from the drift region at a surface of the base region, a gate insulating film formed on the base region between the source region and the drift region, a region formed spaced apart from the base region at a surface of the drift region, a second drain region of a first conductivity type formed spaced apart from the region at the surface of the drift region, a source electrode formed over the first semiconductor substrate and electrically connected to the base region and the source region, a gate electrode formed on the gate insulating film, an electrode formed over the first semiconductor substrate and electrically connected to the region, and a second drain electrode formed over the first semiconductor substrate and electrically connected to the second drain region, the second drain electrode is electrically connected to a reverse current preventing layer of a second conductivity type formed at a surface of a second semiconductor substrate, and the reverse current preventing layer is covered by a well layer of a first conductivity type formed in the second semiconductor substrate.