| 摘要 |
PURPOSE:To increase the capacitance of a capacitor without increasing a chip occupying area and to make it possible to suppress the occurrence of software errors effectively, by forming a memory capacitor by an MOS capacitor region utilizing the surface part of a substrate and a p-n junction capacitor region, which is embedded and formed in the substrate beneath said capacitor region. CONSTITUTION:An MOS capacitor, which is to become a part of memory capaci tor, is obtained as follows: an n<-> type layer 3 is formed on the side wall and the upper surface of a groove 2 in a substrate 1; and a capacitor electrode 5 comprising a first-layer polycrystalline silicon film is formed on the surface of the n<-> type layer 3 through a capacitor insulating film 4. An n<-> type embed ded layer 12 is embedded and formed in the substrate 1 beneath the MOS capaci tor region so that the layer 12 is continued to the n<-> type layer 3, which is the substrate-side electrode of the MOS capacitor. A p<+> type embedded layer 13 is formed in contact with the lower side of the n<-> type embedded layer 12. A part comprising the n<-> type embedded layer 12 and the p<+> type embedded layer 13 becomes the p-n junction capacitor, which constitutes the memory capacitor together with the MOS capacitor. |
