Nonvolatile semiconductor memory device and method for driving the same

Abstract

The nonvolatile semiconductor memory device of the invention includes: bit-line pairs; word lines; memory cells each including a capacitor having a ferroelectric film between electrodes thereof, and a switching element connected to one of the word lines, one of the electrodes of the capacitor being connected to one bit line of the bit-line pairs via the switching element, the other electrode of the capacitor being connected to a common cell plate; sense amplifiers each connected to one of the bit-line pairs; a row decoder for selecting one of the word lines corresponding to an input row address; and a column decoder for selecting at least one of the bit-line pairs corresponding to an input column address. The device further includes: a first driving circuit for precharging the bit lines to a first potential; and a second driving circuit for precharging again the bit-line pair selected by the column decoder to a second potential which is different from the first potential. In the memory device, a potential difference between the first potential and a potential of the common cell plate is smaller than a potential difference which causes polarization inversion in the ferroelectric film, and a potential difference between the second potential and the potential of the common cell plate is equal to or larger than the potential which causes potential inversion in the ferroelectric film.