| 摘要 |
PROBLEM TO BE SOLVED: To provide a nonvolatile semiconductor storage device that suppresses deterioration of reliability due to the rewriting of data.SOLUTION: A method for erasing a NAND type flash memory includes: holding a control gate at 0 V; discharging electrons from a floating gate to a P well 14 by applying a high-voltage erasure pulse Ps to the P well 14; then, holding the control gate at 0 V again; and applying a weak erasure pulse Pw having a voltage lower than that of the erasure pulse Ps, to the P well 14.SELECTED DRAWING: Figure 8 |
