| 摘要 |
PROBLEM TO BE SOLVED: To make an insulating film to effectively share the voltage exerted on a semiconductor layer by providing a high-resistance film to be formed on the insulating film and a semiconductor layer to be formed on this high- resistance film. SOLUTION: An insular high-resistance silicon layer 15 isolated from a p<+> type silicon substrate 11 by an oxide film 12 and the high-resistance film 13 and horizontally isolated from the other element regions by an oxide film 14 is formed on the p<+> type silicon substrate 11. This high-resistance silicon layer 15 is a p<-> type layer or an n<-> type layer having a sufficiently low impurity concentration. A polycrystalline silicon film 16 is buried in the element isolation region and an n<+> type layer 17 of a high impurity concentration as a cathode layer is formed on the surface central part of the high-resistance silicon layer 15. Thereby, a voltage exerted on a semiconductor layer can be effectively shared so as to facilitate an improvement of breakdown voltage of the semiconductor device and separation of a dielectric. |
