| 摘要 |
PROBLEM TO BE SOLVED: To obtain a semiconductor device having a highly reliable breakdown voltage structure where the electric field concentration hardly occurs. SOLUTION: An nwell layer 9 is formed on the surface layer of a p-substrate 10, n-type high potential regions 8, p-type low potential regions 12 and poffset regions 14 are formed on the surface layer of the layer 9, a spiral thin film layer 6 composed of repeats of first conductivity type and second conductivity type thin film layers 4, 5 through an insulation oxide film 18 is formed on the surface of the substrate 10, and a backside electrode 11 is formed on the backside of the substrate 10. When in this structure a positive potential Vs is applied to a high potential electrode 2 with reference to a low potential electrode 3, the potential Vs is also applied to the end of the spiral layer 6 connected to the high potential electrode 2, thus forming a uniform potential distribution over the spiral layer 6. |
