Ferroelectric memory device and method of operating memory cell including ferroelectric capacitor

A ferroelectric memory device comprising:

• first signal electrodes, a ferroelectric layer, and second signal electrodes,
• wherein the second signal electrodes are formed along a direction which intersects the first signal electrodes,
• wherein memory cells each of which comprises a ferroelectric capacitor including at least one of the first signal electrodes, one of the second signal electrodes, and the ferroelectric layer, are formed in regions in which the first signal electrodes intersect the second signal electrodes,
• wherein information is written into a selected memory cell by applying a write voltage between one of the first signal electrodes and one of the second signal electrodes in the selected memory cell,
• wherein information is read from the selected memory cell by applying a read voltage between one of the first signal electrodes and one of the second signal electrodes in the selected memory cell, and
• wherein, provided that the write voltage is ±Vs and the read voltage is one of +Vs and −Vs, |Vs| is less than an absolute value of a saturation voltage at which remanent polarization of the ferroelectric capacitor is saturated.

A method of operating memory cells including ferroelectric capacitors,

• wherein each of the memory cells comprises a first signal electrode, a ferroelectric layer, and a second signal electrode,
• wherein the second signal electrode is formed along a direction which intersects with the first signal electrode,
• wherein each of the memory cells comprises at least the first signal electrode, the second signal electrode, and the ferroelectric layer in a region in which the first signal electrode intersects the second signal electrode, the method comprising:
• a step of writing information into a selected memory cell by applying a write voltage between the first signal electrode and the second signal electrode in the selected memory cell,
• wherein an absolute value of the write voltage is less than an absolute value of a saturation voltage at which remanent polarization of the ferroelectric capacitors is saturated.

A method of operating memory cells including ferroelectric capacitors,

• wherein each of the memory cells comprises a first signal electrode, a ferroelectric layer, and a second signal electrode,
• wherein the second signal electrode is formed along a direction which intersects with the first signal electrode,
• wherein each of the memory cells comprises at least the first signal electrode, the second signal electrode, and the ferroelectric layer in a region in which the first signal electrode intersects the second signal electrode, the method comprising:
• a step of writing information into a the selected memory cell by applying a write voltage between the first signal electrode and the second signal electrode in the selected memory cell, and
• a step of writing information from the selected memory cell by applying a read voltage between the first signal electrode and the second signal electrode in the selected memory cell,
• wherein, provided that the write voltage is ±Vs and the read voltage is one of +Vs and −Vs, |Vs| is less than an absolute value of a saturation voltage at which remanent polarization of the ferroelectric capacitors is saturated.