| 摘要 |
PROBLEM TO BE SOLVED: To provide an NAND flash memory whose writing efficiency can be improved while reducing an erroneous writing operation.SOLUTION: In the NAND flash memory, if the number of times of program operations which have been performed is not equal to a prescribed upper limit number of times, then a program voltage is set to be increased by a first potential difference, and thereafter, the program operation and a verifying operation are performed again. Only if the number of times of the program operations which have been performed is equal to a prescribed number of times, which is set to be less than the upper limit number of times, an intermediate voltage is increased by a second potential difference and is then fixed. |
