| 摘要 |
<p>A non-volatile semiconductor memory device includes a first memory cell which is electrically erasable and programmable and stores data, a second memory cell which is electrically erasable and programmable and has a threshold voltage which is set by performing erase and write operations on the second memory separately from erase and write operations on the first memory, and a sense amplifier comparing currents respectively flowing in the first and second memory cells to sense a state of the first memory cell. A verify voltage supply circuit supplies, in an erase verify operation, control gates of the first and second memory cells with erase verify voltages dependent on an actual value of the threshold voltage of the second memory cell, and supplies, in a write verify operation, the control gates of the first and second memory cells with write verify voltages dependent on an actual value of the threshold voltage of the second memory cell. Hence, the erase and write verify operations can duly be carried out even if the threshold voltage of the second memory cell actually derives from a target value.</p> |
