| 摘要 |
PURPOSE:To simplify the structure and the method of manufacturing a capacitor element, which have been very much complicated so far. CONSTITUTION:A memory cell is formed of an electroconductive film 7, formed on a monocrystalline silicon thin film 3, insulated and separated from a silicon substrate 1 by a buried oxide film 4 and formed on the lower electrode of an N<+> type diffusion layer 3b which becomes the source or the drain of a selective transistor, and a plate electrode 8. According to above-described constitution, the formation of a well becomes unnecessary and a necessary capacitance value can be realized by a small capacitance area having a simple plane structure whereby the structure and the manufacturing method of a capacitor element, which have been very much complicated so far, can be simplified. On the other hand, connection of an N<+> type diffusion area to a P-type well is eliminated whereby a leak current of connection is eliminated in principle, the elongation of cycle of refresh operation necessary for retaining the stored data of a memory cell can be realized and a refresh current can be reduced. |
