| 摘要 |
PURPOSE:To minimize the distance between the transistor and the capacitor and increase the density of the memory cell, by insulating and separating the transistor and the capacitor from each other by a part of the gate insulating film. CONSTITUTION:Gate oxide film 8 and impurity-added poly-Si 9 are placed in layers on Si substrate 1 divided by thick oxide film 2. This is selectively covered with SiO2 mask 12. By etching film 9, its inner part within a specified distance from the mask edge is removed. The etched part is covered with gate insulating film 10. The place below the canopy and the entire surface are covered with impurity-added Si layer 11. Next, plasma etching is operated from the surface and it is stopped at a suitable place, and thereby poly-Si film 11 is retained below SiO2 film 12, and diffused layer 6 of conduction type opposite to that of the substrate is formed. By this structure, transistor Tr and capacitor C are insulated and separated from each other by a part of gate insulating film 10, so that their distance is reduced nearly to zero. Consequently, high density can be obtained for the memory cell. |
