| 摘要 |
PURPOSE:To enhance the performance of a semiconductor memory device by composing the capacitor of the first memory cell of a diffused layer of the surface of a substrate, and a cell plate, and the capacitor of the second memory cell of a cell plate and a capacitor electrode, thereby increasing the area ratio of the capacitor in the memory cell. CONSTITUTION:A field oxide film 2 is formed on a silicon substrate 1, As or P is diffused in the capacitor forming region of the first memory cell to form an N<-> type layer 3, and a cell plate 5 is formed by the first layer polycrystalline silicon film. Then, the second gate oxide film 6 is formed on the overall surface, and the capacitor electrode 7 of the second memory cell is formed to superpose the layer 3 on the plate 5. Thus, since the capacitors of the two adjacent memory cells are superposed on the same region, the occupy ing area rate of the memory cell and hence the occupying area rate of the capacitor can be increased as compared with the conventional one, the charge storage amount is increased to improve S/N ration, thereby increasing the margin for a sense refresh circuit. |
