| 摘要 |
PURPOSE:To prevent a breakdown voltage from decreasing on the surface of a p-n injunction and on the bent portion in a substrate by surrounding the periphery of a pattern of the p-n junction by a groove buried with polysilicon used as a field plate. CONSTITUTION:An n type layer 12 is formed by a normal epitaxial technique on an n<+> type semiconductor substrate 11, and then a p type region 13 is formed by normal diffusing technique on the layer 12. Then, a groove 14 is formed deeper than the p type layer around the p type region by known etching to expose the p-n junction around the groove so that the p-n junction is formed in the groove in mesa shape. Then, for example, an SiO2 film 5 is formed on the surface of the groove and the surface of the substrate, the groove 14 is buried and returned by growing the polysilicon by chemical vapor phase growing method to form a polysilicon buried layer 16. Subsequently, polysilicon is ground along the substrate, to form an SiO2 film 17 on the surface of the substrate by thermal oxidizing method. Then, a window is opened at the film 17 by the normal technique, and an upper electrode is formed so that the extension is connected with the layer 16. |
