| 摘要 |
PROBLEM TO BE SOLVED: To provide a semiconductor device in which breakdown voltage on the periphery of an element can be set higher than that of the element. SOLUTION: On the periphery of an element in a semiconductor substrate 1, a level difference 12 is provided at the boundary of a guard ring part Z1 and a connecting part Z2. At a lower part of the level difference 12, an impurity diffusion region 10 for p-type guard ring is formed on the surface layer part of the substrate 1 and depleted completely before an element breaks down. At a higher part of the level difference 12, an impurity diffusion region 11 for connection is formed in order to connect the element part with the impurity diffusion region 10 for guard ring. The impurity diffusion region 11 for connection is doped more heavily than the impurity diffusion region 10 for guard ring and the surface part is not depleted completely when the element breaks down. Upper surface 10a of the impurity diffusion region 10 for guard ring is located lower than the upper limit surface Llimit of depletion in the impurity diffusion region 11 for connection. |
