Kabushiki Kaisha Toshiba

Sumiko Doumae

Daisaburo Takashima

Yukihito Oowaki

Yoshiaki Takeuchi

The sense amplifier detects and amplifies a signal read via bit lines from the ferroelectric capacitor of the memory cell. The dummy capacitor provides a reference voltage to bit lines. The dummy capacitor includes a first dummy capacitor and a second dummy capacitor. The first dummy capacitor is provided with a first dummy plate potential at one end to set the reference voltage to a certain potential. The other end is connected to the bit line. The second dummy capacitor is provided with a second dummy plate potential at one end to fine-tune the reference voltage from the certain potential. The other end thereof is connected to the bit line.

Semiconductor memory device

A ferroelectric memory is provided with a voltage generating circuit configured to generate prescribed driving potential, a driving interconnection to which the driving potential is applied, a plurality of memory cells connected to the driving interconnections and an internal voltage comparison circuit configured to compare inputted potential and to output results thereof. A plurality of voltage monitoring interconnections are provided to connect between a portion of the driving interconnection disposed at a position distant from the voltage generating circuit on the substrate and the internal voltage comparison circuit. The internal voltage comparison circuit compares potential inputted through the voltage monitoring interconnection with the driving potential.

A semiconductor memory device includes a memory cell array of memory cells each including a cell transistor and a ferroelectric capacitor; a sense amp circuit operative to sense/amplify a signal read out of the ferroelectric capacitor through a pair of bit lines; a pair of decoupling transistors provided on the pair of bit lines to decouple the bit lines; a control circuit operative to provide a control signal to the gates of the decoupling transistors to control conduction of the decoupling transistors; and a dummy capacitor provided in connection with at least either one of the pair of bit lines between the decoupling transistors and the sense amp circuit. The control circuit is configured to be capable of turning the decoupling transistors from on to off when a certain period of time elapsed after the beginning of reading.

A ferroelectric random access memory is disclosed, which comprises a cell array including a plurality of memory cells each having a ferroelectric memory device and a cell selecting transistor connected in series to the ferroelectric storage device, and imprint restricting circuit configured to restrict generation of an imprint by setting a polarization amount of a ferroelectric film of the ferroelectric memory device in the memory cell to an amount smaller than a polarization amount generated at a normal write time.

Ferroelectric random access memory

A ferroelectric memory device comprises a word line, first and second bit lines cross to the word line, a memory cell including a first transistor a gate of which is coupled to the word line and one of source and drain of which is coupled to the first bit line, a second transistor a gate of which is coupled to the word line and one of source and drain of which is coupled to the second bit line, and a ferroelectric cell capacitor coupled to the other of source and drain of the first and second transistor, and first and second capacitors each coupled via a switching transistor to a respective one of the first and second bit lines, wherein first and second voltages complementary to each other are applied to the first and second bit lines, via the first and second capacitors, respectively.

Growing community of inventors

Yokohama, Japan

Sumiko Doumae