| 摘要 |
<p>PURPOSE:To provide a nonvolatile semiconductor storage device, in which the leak current in the low electric field of a gate oxide film causing the deterioration of data-holding characteristics and the improvement of said characteristics can be contrived. CONSTITUTION:A NAND cell-type EEPROM is equipped with a write-potential generation circuit 27 for applying a write voltage Vw to the gate-insulating film of a transistor constituting a memory cell 21 at the time of writing data, with an erase-potential generation circuit 28 for applying an erase voltage Ve to the gate-insulating film at the time of erasing data and with a stress- relaxation potential generation circuit 29 for applying a stress-relaxation voltage Vs to the gate-insulating film to relax a stress given to the gate-insulating film after the data write operation and data erase operation, and the stress- relaxation voltage Vs is set in the manner of satisfying the relation between ¦Vs¦<¦Vw¦ and ¦Vs¦<¦Ve¦.</p> |
