Nonvolatile semiconductor storage device
First Claim
1. A nonvolatile semiconductor storage device comprising:
- a cell array including a cell unit, a selection wire and a dummy wire, the cell unit including a memory string in which a plurality of memory cells for storing data are connected in series and one or more dummy cells being provided at one end of the memory string, the selection wire connecting to each of the memory cells, and the dummy wire connecting to each of the dummy cells; and
a drive circuit applying voltages to the selection wire and the dummy wire during erase operation for erasing data in the memory cells,the dummy cell adjacent to the memory string being defined as a first dummy cell, the memory cell adjacent to the first dummy cell being defined as a first memory cell, the memory cell adjacent to the first memory cell being defined as a second memory cell, a voltage applied to the dummy wire connected to the first dummy cell being defined as a first dummy wire voltage, a voltage applied to the selection wire connected to the first memory cell being defined as a first selection wire voltage, and a voltage applied to the selection wire connected to the second memory cell being defined as a second selection wire voltage, andwhen the second selection wire voltage is lower than the first dummy wire voltage in the erase operation, the drive circuit controlling the voltages so that a difference between the first dummy wire voltage and the second selection wire voltage is less than a difference between the first dummy wire voltage and the first selection wire voltage.
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Accused Products
Abstract
A nonvolatile semiconductor storage device according to an embodiment includes a drive circuit. A voltage applied to a dummy wire connected to a first dummy cell adjacent to a memory string is defined as a first dummy wire voltage, a voltage applied to a selection wire connected to a first memory cell adjacent to the first dummy cell is defined as a first selection wire voltage, and a voltage applied to a selection wire connected to a second memory cell adjacent to the first memory cell is defined as a second selection wire voltage. When the second selection wire voltage is lower than the first dummy wire voltage in an erase operation, the drive circuit controls voltages so that a difference between the first dummy wire voltage and the second selection wire voltage is less than a difference between the first dummy wire voltage and the first selection wire voltage.
11 Citations
18 Claims
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1. A nonvolatile semiconductor storage device comprising:
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a cell array including a cell unit, a selection wire and a dummy wire, the cell unit including a memory string in which a plurality of memory cells for storing data are connected in series and one or more dummy cells being provided at one end of the memory string, the selection wire connecting to each of the memory cells, and the dummy wire connecting to each of the dummy cells; and a drive circuit applying voltages to the selection wire and the dummy wire during erase operation for erasing data in the memory cells, the dummy cell adjacent to the memory string being defined as a first dummy cell, the memory cell adjacent to the first dummy cell being defined as a first memory cell, the memory cell adjacent to the first memory cell being defined as a second memory cell, a voltage applied to the dummy wire connected to the first dummy cell being defined as a first dummy wire voltage, a voltage applied to the selection wire connected to the first memory cell being defined as a first selection wire voltage, and a voltage applied to the selection wire connected to the second memory cell being defined as a second selection wire voltage, and when the second selection wire voltage is lower than the first dummy wire voltage in the erase operation, the drive circuit controlling the voltages so that a difference between the first dummy wire voltage and the second selection wire voltage is less than a difference between the first dummy wire voltage and the first selection wire voltage. - View Dependent Claims (2, 3, 4, 5, 6, 7, 18)
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8. A nonvolatile semiconductor storage device comprising:
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a cell array including a cell unit, a selection wire and a dummy wire, the cell unit including a memory string in which a plurality of memory cells for storing data are connected in series and one or more dummy cells being provided at one end of the memory string, the selection wire connecting to each of the memory cells, and the dummy wire connecting to each of the dummy cells; and a drive circuit for applying voltages to the selection wire and the dummy wire during erase verification operation for confirming erasing of data in the memory cells, the dummy cell adjacent to the memory string being defined as a first dummy cell, the memory cell adjacent to the first dummy cell being defined as a first memory cell, the memory cell adjacent to the first memory cell being defined as a second memory cell, a voltage applied to the dummy wire connected to the first dummy cell being defined as a first dummy wire voltage, a voltage applied to the selection wire connected to the first memory cell being defined as a first selection wire voltage, and a voltage applied to the selection wire connected to the second memory cell being defined as a second selection wire voltage, and when the second selection wire voltage is lower than the first dummy wire voltage in the erase verification operation, the drive circuit controlling the voltages so that a difference between the first dummy wire voltage and the second selection wire voltage is less than a difference between the first dummy wire voltage and the first selection wire voltage. - View Dependent Claims (9, 10, 11, 12, 13)
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14. A nonvolatile semiconductor storage device comprising:
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a cell array including a cell unit, a selection wire and a gate wire, the cell unit including a memory string in which a plurality of memory cells for storing data are connected in series and a selection gate transistor being provided at one end of the memory string, the selection wire connecting to each of the memory cells, and the gate wire connecting to the selection gate transistor; and a drive circuit applying voltages to the selection wire and the gate wire during erase verification operation for confirming erasing of data in the memory cells, the memory cell adjacent to the selection gate transistor being defined as a first memory cell, the memory cell adjacent to the first memory cell being defined as a second memory cell, the memory cell adjacent to the first memory cell being defined as a second memory cell, a voltage applied to the gate wire being defined as a gate wire voltage, a voltage applied to the selection wire connected to the first memory cell being defined as a first selection wire voltage, and a voltage applied to the selection wire connected to the second memory cell being defined as a second selection wire voltage, and when the second selection wire voltage is lower than the gate wire voltage in the erase verification operation, the drive circuit controlling the voltages so that a difference between the gate wire voltage and the second selection wire voltage is less than a difference between the gate wire voltage and the first selection wire voltage. - View Dependent Claims (15, 16, 17)
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Specification