| 摘要 |
<p>PURPOSE:To shorten time required for erasing operation, in the case where the existence of a memory cell with an erasing defect is confirmed, by starting a re-erasing and verifying operation from the address stored in a storage part. CONSTITUTION:When the threshold voltage of the cell area with erasing performed in a memory cell and a cell part 4 is lowered, a read-out confirmation whether the erasing is normally finished or not is performed by an erase comparator 5. An address to confirm the read-out is given to the cell part 4 by an internal address part 1; and by receiving this address, the selection of a cell 4 in the memory cell 4 is performed by a decoder part 3. Then, the address in the memory cell with the erasing defect is stored in a storage part 2 for the address with erasing defects. After that, a verifying operation besides erasing is started from the defective address stored in the storage part 2. Thus, the time for erasing operation including erasing and/or erasing and verifying is shortened.</p> |
