Patent ID: 7843740
Filing Date: 2010-11-30
Classification: G11C,H01L

Abstract:
1. A method for driving a nonvolatile semiconductor memory device having a semiconductor layer having a channel and source/drain regions provided on both sides of the channel, a first insulating film provided on the channel, a floating electrode provided on the first insulating film, a second insulating film provided on the floating electrode, and a gate electrode provided on the second insulating film, the nonvolatile semiconductor memory device changing its data memory state by injection of charges into the floating electrode, the method comprising, to achieve a state in which charges having a first polarity are injected into the floating electrode: providing a first potential difference between the semiconductor layer and the gate electrode to inject charges having the first polarity into the second insulating film; subsequently providing a second potential difference between the semiconductor layer and the gate electrode to inject charges having a second polarity opposite to the first polarity into the second insulating film; and subsequently providing a third potential difference between the semiconductor layer and the gate electrode to inject charges having the first polarity into the floating electrode.