Patent ID: 7898029

Claim:
A semiconductor device, comprising: a semiconductor substrate; a first semiconductor region of a first conductivity type formed in said semiconductor substrate; an MOS transistor of the first conductivity type formed at a surface of said semiconductor substrate, said MOS transistor of the first conductivity type including a gate electrode, a source electrode, a drain electrode, a second semiconductor region of a second conductivity type having a channel formed by a potential difference between said gate electrode and said source electrode, formed in said first semiconductor region and electrically connected to said drain electrode, a third semiconductor region of the first conductivity type formed in said second semiconductor region and electrically connected to said source electrode, and a fourth semiconductor region of the first conductivity type formed in said second semiconductor region and electrically connected to said drain electrode; a fifth semiconductor region of the second conductivity type formed in said first semiconductor region, opposed to said second semiconductor region with said first semiconductor region therebetween and electrically connected to said gate electrode; and an electrode formed on said first semiconductor region located between said second and fifth semiconductor regions with an insulating film therebetween, and electrically connected to said gate electrode.