| 摘要 |
PROBLEM TO BE SOLVED: To provide a semiconductor memory device capable of satisfactorily refreshing a memory cell while having a small refresh busy rate. SOLUTION: A refresh operation for recovering deteriorated logical data of the memory cell includes: a first refresh operation in which a first potential higher than a potential of a gate electrode in a data retentive state is applied to the gate electrode under the state that a potential almost equal to a potential of a source layer is applied to a drain layer, and thereafter a potential of the gate electrode in a data retentive state is applied to the gate electrode, thereby a first current passes to the memory cell; and a second refresh operation in which a second potential and third potential higher than the potential of the gate electrode in the data retentive state are applied to the gate electrode and the drain layer, thereby the second current passes to the memory cell, and the memory cell is shifted to an equilibrium state in which a first current amount and a second current amount flowing during one cycle of the refresh operation become substantially equal. COPYRIGHT: (C)2009,JPO&INPIT
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