Patent attributes
A semiconductor device has a semiconductor substrate of a first conductivity type, a first well region of the first conductivity type which is formed to extend from the surface of the semiconductor substrate toward the inside thereof, a pair of second well regions of a second conductivity which are formed to extend from the surface of the semiconductor substrate toward the inside thereof in such as manner as to sandwich the first well region therebetween, and a third well region of the second conductivity type which is formed under each of the first well region and the pair of second well regions in the semiconductor substrate. The third well region electrically connects the pair of second well regions to each other. The first well region has at least a portion thereof connected to the region of the semiconductor substrate in which the third well region is not formed.
