Patent ID: 7436691
Filing Date: 2008-10-14
Classification: G11C

Abstract:
1. A semiconductor storage devices, comprising: a bit line; a word line; a plate line; a ferroelectric capacitor having a ferroelectric substance between electrodes, one of the electrodes being connected to the plate line, the ferroelectric capacitor configured to store data; a selection transistor connected between the other of the electrodes of the ferroelectric capacitor and the bit line, the selection transistor configured to selectively connect the ferroelectric capacitor to the bit line on the basis of a potential on the word line; a bit line driver corresponding to the bit line to drive the bit line; a word line driver corresponding to the word line to drive the word line; and a plate line driver corresponding to the plate line, the plate line driver including a plurality of plate voltage lines configured to apply a plurality of different voltage values to the plate line, the plate line driver connecting a common single plate voltage line included in the plate voltage lines to the plate line when data is written or rewritten into the ferroelectric capacitor, wherein when the ferroelectric capacitor is initialized, the plate line driver is capable of connecting the plate voltage lines including a higher voltage line and a lower voltage line to the plate line, the higher volume line has a higher voltage in absolute value than that of the lower voltage line, when data is read from, written into, or rewritten into the ferroelectric capacitor, the plate line driver is capable of connecting a ground or the lower voltage line to the plate line.