Patent ID: 8716811

Claim:
A semiconductor device comprising: a first conduction-type semiconductor substrate divided along one direction into a terminal region and an active region, the active region for active elements; a first semiconductor region of a first conduction-type formed on the semiconductor substrate; a second semiconductor region of a second conduction-type formed on a surface of the first semiconductor region and within the active region; a third semiconductor region of the second conduction-type formed separated from the second semiconductor region on the surface of the first semiconductor region and within the terminal region but adjacent active region; a fourth semiconductor region of the second conduction-type formed separated from both the second semiconductor region and the third semiconductor region on the surface of the first semiconductor region and within the terminal region; and a first electrode connected to the second semiconductor region and the third semiconductor region, wherein, the third semiconductor region is between the second and fourth semiconductor regions, the fourth semiconductor region is separated from the third semiconductor region by a continuous gap between said third and fourth semiconductor regions, and the length of the gap in the one direction is equal to or shorter than a distance of a depletion layer that forms from a side of the third semiconductor region to a side of the fourth semiconductor region when a reverse voltage is applied to the first electrode.