Nonvolatile semiconductor memory device and a method of erasing data thereof
AssigneeKabushiki Kaisha Toshiba
InventorsNorihiro Fujita, Hiroshi Nakamura
Life of this patent
Estimating the term…
Abstract
A nonvolatile semiconductor memory device comprises memory cell array constituted of a plurality of memory blocks which electrically rewritable memory cells are arranged, before erasing data of all of said memory cells in the selected memory block in a plurality of said memory blocks, preprogram is performed to shift all threshold voltages of all of said memory cells in said selected memory blocks to positive.
Claims20
A nonvolatile semiconductor memory device comprising:
- memory cell array constituted of a plurality of memory blocks which electrically rewritable memory cells are arranged,
- at the time of an erasing operation, before erasing the data of all of said memory cells in memory blocks selected from said plurality of memory blocks, threshold voltages of all of said memory cells in said selected memory blocks are shifted to be positive.
A nonvolatile semiconductor memory device comprising:
- memory cell array constituted of a plurality of memory blocks which an electrically rewritable memory cells are arranged,
- said plurality of memory blocks are composed of the first domain and the second domain respectively,
- when the data of a specific memory cell of said memory cells in said second domain of a memory block selected from said plurality of memory blocks is the first value,
- writing or erasing of the data to said selected memory blocks is permitted,
- when the data of said specific memory cell is the second value,
- writing or erasing of the data to said selected memory blocks is prohibited,
- when writing or erasing of the data to said memory blocks is permitted,
- before erasing the data of all of said memory cells in said selected memory blocks at the time of the erasing operation,
- all threshold voltages of all of said memory cells of said first domain in said selected memory block are shifted to be positive.
A method of erasing data of a nonvolatile semiconductor memory device comprising:
- memory cell array constituted of a plurality of memory blocks which electrically rewritable memory cells are arranged,
- before erasing the data of all of said memory cells in memory blocks selected from said plurality of memory blocks at the time of erasing operation,
- all threshold voltages of all of said memory cells in said selected memory blocks are shifted to be positive.
A method of erasing data of a nonvolatile semiconductor memory device comprising:
- memory cell array constituted of a plurality of memory blocks which an electrically rewritable memory cells are arranged,
- said plurality of memory blocks are composed of the first domain and the second domain respectively,
- when the data of a specific memory cell of said memory cells in said second domain of a memory block selected from said plurality of memory blocks is the first value,
- writing or erasing of the data to said selected memory blocks is permitted,
- when the data of said specific memory cell is the second value,
- writing or erasing of the data to said selected memory blocks is prohibited,
- when writing or erasing of the data to said memory blocks is permitted,
- before erasing the data of all of said memory cells in said selected memory blocks at the time of the erasing operation,
- all threshold voltages of all of said memory cells of said first domain in said selected memory block are shifted to be positive.
Dependencies are inferred from the claim text.