| 摘要 |
PROBLEM TO BE SOLVED: To suppress the spreads of the depletion layers of a semiconductor device which tend to reach the peripheral edge portions of the substrate, and to stabilize the withstanding voltage characteristic by forming a ring-form electrode via a thin insulating film in adjacent to the upper portion of a ring- form double diffusion layer surrounding a cell region, provided in the peripheral edge portion of its aubstrate so that the electrode overlaps partially with the double diffusion layer. SOLUTION: In the peripheral edge portion of a pellet, a shallow N<+> -type impurity diffusion layer 307 is formed and thereabouts a P-type impurity diffusion layer 301 is formed. Also, above the end portion of a double diffusion layer comprising the layers 301, 307, an electrode 304a is formed via a gate oxide film 201. The electrode 304a is connected via a contact hole with an upper electrode 402b covering the exposure surface of the N<+> -type impurity diffusion layer 307. Thereby, suppressing the spread of the depletion layers formed in the peripheries of a P-type base region 302 and a P-type impurity diffusion layer 105, the spread of the depletion layers are prevented from reaching the vicinities of the end surfaces of the pellet and cracks are generated so as to stabilize the withstanding voltage characteristic of a MOSFET. |
