| 摘要 |
PROBLEM TO BE SOLVED: To effectively prevent occurrence of a leakage current due to a deep trap, by a method wherein a position of a depletion layer is controlled s that the deep trap does not enter a lower electrode by a voltage applied thereto. SOLUTION: Each work line 1.7 disposed on an isolated insulation film 1.2 can be covered with a silicon nitride film 1.21 to be protected, and a bit line 1.9 is formed via a trip electrode composed of a polycrystal silicon 1.8 connected to a drain 1.4 of MOS transistors, and is covered with a silicon oxide film 1.10 to be flatten. An opening part is formed above a source 1.5 and a conductive film by etching, and a polycrystalline silicon film is formed, and a lower electrode 1.11 of an accumulation capacitor is formed. Accordingly, as an electrical position of Pn junction can be controlled at a different position from a metallurgical position, it is possible to prevent a deep trap from entering a depletion layer and secure a memory holding time required in DRAMs of several tens of mega- to giga-bit class. |
