| 摘要 |
For a memory cell comprising: a pair of memory nodes for holding a pair of complementary voltages; a pair of switching elements for controlling the connection between each memory node and a bit line corresponding to the memory node according to ON/OFF control by a common word line; and a pair of ferroelectric capacitors each of which is connected to a plate line and corresponding one of the memory nodes, storing operation of the memory cell is carried out by swinging the voltage of the plate line between a first voltage that is higher than power supply voltage of the memory cell and a second voltage that is lower than the ground potential while keeping the switching elements in off states, thereby remanent polarization of the ferroelectric capacitors is made larger. In addition, recall operation of the memory cell is carried out by driving the plate line to a third voltage that is higher than the power supply voltage or a fourth voltage that is lower than the ground potential so as to enlarge operation margin. By such storing operation and recall operation, the reliability of nonvolatile memory under a low power supply voltage can be improved.
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