| 摘要 |
<p>PROBLEM TO BE SOLVED: To achieve accurate verifying, if a threshold voltage of a reference cell is set outside a target value in an electrically erasable and writable nonvolatile semiconductor storage device such as a flash memory. SOLUTION: By erasing and writing under the same voltage condition as a reference cell 21, a threshold voltage of a verifying voltage control cell 79 is set. When verifying, the verifying voltage control cell 79 functions as resistance to supply, to a control gate of the reference cell 21, a verifying voltage VEB 21 or VWB 21 corresponding to a real value of a threshold voltage of the reference cell 21.</p> |
