A controller repeats an erase operation, an erase verify operation, and a step-up operation. A first storage unit stores a value of an erase start voltage applied first as an erase voltage when a series of erase operations are executed. A second storage unit stores a value of an erase completion voltage...http://www.google.fr/patents/US7907463?utm_source=gb-gplus-shareBrevet US7907463 - Non-volatile semiconductor storage device
