| 摘要 |
PROBLEM TO BE SOLVED: To provide a high withstanding voltage semiconductor device that keeps an element less susceptible to damage than existing high withstanding voltage semiconductor devices when a voltage exceeding a breakdown voltage is applied.SOLUTION: In a high withstanding voltage semiconductor device 1 which has a semiconductor base 10 comprising a lamination of a semiconductor substrate and an epitaxial layer, an element separation region 20 comprising a surface diffusion layer and a buried diffusion layer, a high voltage circuit 40, a high withstanding voltage MOSFET 50 and a boundary region 60, and in which the high voltage circuit 40, the high withstanding voltage MOSFET 50 and the boundary region 60 are all formed in the same floating island region 30, and a RESURF region 70 is formed in a peripheral portion of the floating island region 30, within the boundary region 60, in the section where surface diffusion layers 22 sandwiching the boundary region from opposite sides have the shortest interval, buried diffusion layers 24 sandwiching the boundary region 60 from the opposite sides have a shorter interval than the surface diffusion layers 22 sandwiching the boundary region 60 from the opposite sides. |
