| 摘要 |
PURPOSE:To provide a stacked capacitor-type DRAM cell whose memory capacity can be increased with its area being made small on the substrate. CONSTITUTION:This DRAM cell is constituted of a substrate 11, diffusion layers 12, 13, an interlayer insulating film 14, gates (word lines) 15, 20 which are formed of a polysilicon film, a lower capacitor electrode 16 which is formed of polysilicon films 32, 33, a thin film 17 of a large permittivity, an upper capacitor electrode 18 formed of a polysilicon film, a field oxide film 19, an insulating film 21, and a bit line 22. If the polysilicon film 32 is formed thick and an area of an external edge section (A section) of the polysilicon film 16 is increased, a surface area of the thin film 17 is increased. If the polysilicon film 32 is formed thick, a central dent of the polysilicon film 16 becomes deep and then a surface area of the thick film 17 is increased. By this method, a memory capacity can be increased. |
