| 摘要 |
PURPOSE:To realize the high density integration of a device, and prevent, at the same time, an inverse conductivity type region from forming in the epitaxial layer of an element forming region, by making the region of a first conductivity type buried layer formed on a first conductivity type substrate retreat from the region of a second conductivity type buried layer. CONSTITUTION:By side-etching of the side-wall of an oxide film 101 applying a nitrogen film 201 to a mask, the edge position of an oxide film 101 is made to reateat as far as a specified position in a first region. By applying the nitrogen film 201 to a mask, an oxide film 102 is formed. Both of the oxide films 101 and 202 are eliminated, and an n<-> type epitaxial layer 4 of low impurity concentration is formed on a semiconductor substrate 1 on the surface layer of which an n<+> type buried layer 22 and a p<+> type buried layer 3 are formed. Even if the floating-up diffusion of p-type impurity in the p<+> type buried layer 3 is taken into account, the region of the p<+> type buried layer 3 after the n<-> type epitaxial layer 4 is formed can be reduced, because the region of the p<+> type buried layer 3 is made to retreat from the region of the n<+> type buried layer 22.
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