A spread stacked capacitor (SSC) cell for 64 Mbit DRAMs

In order to realize a small memory cell area for 64-Mb DRAMs (dynamic RAMs), a spread stacked capacitor (SSC) cell is proposed. In this cell, the storage electrode of the first memory cell is expanded to the neighboring second memory cell area. Then, the storage electrode of the second memory cell is also expanded to the first memory cell area. Therefore, each storage electrode can occupy two memory cell areas, and the SSC cell can enlarge the storage capacitance to 1.8 times that of the conventional stacked capacitor cell. When the SSC cell is applied to 64-Mb DRAMs, a 27-fF storage capacitance can be achieved using 4-nm-SiO/sub 2/-equivalent-thickness dielectric film.<
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