Nonvolatile semiconductor memory device
AssigneeKabushiki Kaisha Toshiba
InventorYasushi Nakajima
Life of this patent
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Abstract
According to one embodiment, an erase verification execution unit that makes an erase verify operation of a memory cell, on which an erase operation is performed, to be performed, a number-of-erase-verifications counting unit that counts the number of erase verifications of a memory cell on which the erase operation is performed, and a number-of-erase-verifications setting unit that sets a minimum number of erase verifications for the next time based on the current number of erase verifications counted by the number-of-erase-verifications counting unit are included.
Claims19
A nonvolatile semiconductor memory device comprising:
- a memory cell array in which a plurality of memory cells is provided;
- an erase execution unit that performs an erase operation of data stored in the memory cells;
- an erase verification execution unit that performs an erase verify operation of a memory cell, on which the erase operation is performed;
- a number-of-erase-verifications counting unit that counts a number of erase verifications of a memory cell on which the erase operation is performed;
- and
- a number-of-erase-verifications setting unit that sets a minimum number of erase verifications for a next time based on the current number of erase verifications counted by the number-of-erase-verifications counting unit.
A nonvolatile semiconductor memory device comprising:
- a memory cell array in which a plurality of memory cells is provided;
- an erase execution unit that performs an erase operation of data stored in the memory cells;
- an erase verification execution unit that performs an erase verify operation of a memory cell, on which the erase operation is performed;
- a number-of-writes/erasures counting unit that counts a number of writes/erasures of the memory cells;
- and
- a number-of-erase-verifications setting unit that sets a minimum number of erase verifications for a next time based on the number of writes/erasures counted by the number-of-writes/erasures counting unit.
Dependencies are inferred from the claim text.