| 摘要 |
PURPOSE: A method for erasing a flash memory cell is provided to reduce the time required in the whole erase process, and also to accord the final threshold voltage after the erase process to a target threshold voltage more accurately. CONSTITUTION: The method includes several steps: an erase step of dropping a threshold voltage of the cell sufficiently lower than a target threshold voltage by using an erase means lowering the threshold voltage of the cell connected to the source of the flash memory cell; a recovery step of adjusting the threshold voltage of the cell lowered sufficiently than the target threshold voltage in the erase step to be close to the target threshold voltage by using a program means(3) increasing the threshold voltage of the cell by being connected to a drain of the flash memory cell; and a program step of adjusting the threshold voltage of the cell close to the target threshold voltage to the target threshold voltage accurately by using the program means.
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