Sanyo Electric Co., Ltd.

Naofumi Sakai

Shigeharu Matsushita

Hideaki Miyamoto

Yoshiyuki Ishizuka

Kouichi Yamada

Yoh Takano

Toru Dan

A memory capable of suppressing disturbance causing disappearance of data in a nonselected memory cell is provided. This memory comprises a memory cell array including a bit line, a word line arranged to intersect with the bit line and memory cells connected between the bit line and the word line, for accessing a selected memory cell thereby deteriorating a remanent polarization in an arbitrary memory cell and thereafter performing recovery for recovering all memory cells to remanent polarizations immediately after a write operation or remanent polarizations subjected to single application of a voltage applied to a nonselected memory cell in the access.

Memory

A memory capable of inhibiting a non-selected cell from disturbance is provided. This memory comprises a bit line, a word line arranged to intersect with the bit line and first storage means connected between the bit line and the word line, for applying voltages of opposite directions to the first storage means of a non-selected memory cell by the same number of times or substantially applying no voltages throughout a read operation and a rewrite operation while varying a rewriting method with a case of reading first data by the read operation and with a case of reading second data by the read operation.

Memory having storage means

A memory capable of suppressing reduction of a reading voltage in data reading regardless of dispersion in a manufacturing process is provided. This memory comprises charge storage means, a first field-effect transistor and data determination means. The memory sets a voltage between a control terminal and a remaining first terminal of the first field-effect transistor to a threshold voltage for bringing the first field-effect transistor into an OFF-state in the vicinity of a boundary state between ON- and OFF-states through the threshold voltage of the first field-effect transistor.

A memory capable of easily setting a reference potential and correctly determining data is provided. This memory comprises a ferroelectric capacitor holding data, and a driving line and a data line linked with the ferroelectric capacitor. The memory applies a voltage pulse to the ferroelectric capacitor through the driving line when reading the data thereby generating a negative potential on the data line if the ferroelectric capacitor holds first data, or generating a positive potential on the data line if the ferroelectric capacitor holds second data.

A memory capable of suppressing disturbance causing disappearance of data from a nonselected memory cell is provided. This memory applies a second voltage of polarity reverse to that of a first voltage applied to a nonselected memory cell in a read operation to at least the nonselected memory cell in addition to the read operation collectively performed on all memory cells connected to a selected word line.

A memory capable of suppressing disturbance is provided. This memory activates each of a selected word line and a bit line corresponding to unrewritten storage means while keeping potential difference therebetween at a level not more than a prescribed value and differentiates the length of a period for applying a voltage for rewriting to each of the selected word line and a bit line corresponding to rewritten storage means from the length of a transition period of the potential of at least either the word line or the bit line corresponding to the unrewritten storage means when performing a rewrite operation on partial selected storage means or performing no rewrite operation on all selected storage means.

A memory capable of suppressing disturbance is provided. This memory comprises a bit line, a word line arranged to intersect with the bit line and first storage means connected between the bit line and the word line, and applies prescribed reverse voltages to at least non-selected first storage means connected to a non-selected word line substantially identical times respectively or substantially applies no voltage through a read operation and a rewrite operation.

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Gifu, Japan

Naofumi Sakai