Kabushiki Kaisha Toshiba

Toshiba Memory Corporation

Sandisk Technologies Inc.

Takahiko Sasaki

Tomonori Kurosawa

Takayuki Tsukamoto

Hiroshi Kanno

Atsushi Kawasumi

Nobuaki Otsuka

Rieko Funatsuki

Takafumi Shimotori

Shuso Fujii

Yuri Terada

Koji Hosono

Takeshi Yamaguchi

Osamu Hirabayashi

Kazushige Kanda

Yoichi Minemura

Gopinath Balakrishnan

Masahiro Kamoshida

Kazuaki Kawaguchi

Go Shikata

Yuki Fujimura

Yasuhisa Takeyama

Katsuaki Sakurai

Mizuki Uda

According to one embodiment, a semiconductor memory device includes a plurality of memory cells; a first circuit configured to convert first data into second data relating to an order of thresholds of the memory cells; and a second circuit configured to perform a write operation on the memory cells based on the second data.

Semiconductor memory device

According to one embodiment, a semiconductor memory device includes first and second memory cells, a word line, first and second bit lines, a sense amplifier and a driver. The first and second memory cells have first and second threshold voltages, respectively. The word line is electrically connected to the first and second memory cells. The first and second bit lines are electrically connected to the first and second memory cells, respectively. The driver increases gradually the voltage of the word line. When the voltage of the word line is increased gradually by the driver, the sense amplifier senses the first and second threshold voltages in ascending order.

Semiconductor memory device configured to sense memory cell threshold voltages in ascending order

A semiconductor memory device according to an embodiment includes: a first wiring line extending in a first direction; a second wiring line extending in a second direction, the second direction intersecting the first direction; a variable resistance film disposed at an intersection of the first wiring line and the second wiring line; a channel body disposed at a first end of the first wiring line; a third wiring line electrically connected to the first wiring line via the channel body; and a gate wiring line extending in the first direction and facing the channel body from the second direction.

A semiconductor memory device includes a memory cell array having first wires, a second wire, and memory cells connected to the first and second wires, and a control circuit that can apply writing voltages to the second wire. One of the memory cells connected to the selected second wire and a selected first wire is a selected memory cell. One of the memory cells connected to the selected second wire and an unselected first wire is a semi-selected memory cell. When writing data into the selected memory cell, the control circuit selects one from the writing voltages and applies the one writing voltage to a third wire connected to the selected second wire. The control circuit selects the one writing voltage, based on a first current flowing through the second wire when each of the memory cells connected to the selected second wire are set as semi-selected memory cells.

Semiconductor memory device including semi-selectable memory cells

According to one embodiment, a temperature sensor includes: a voltage generating part generating (2&#x2212;1)-midpoint voltages (N is a natural number equal to or larger than 2) based on a reference voltage which does not depend on a temperature; a sense part generating a temperature sensing voltage which depends on the temperature; and an arithmetic part is configured to generate N-bit temperature data by executing first to N-th operations each comparing the temperature sensing voltage with one of the (2&#x2212;1)-midpoint voltages.

Temperature sensor with successive AD conversion with selective comparisons

A nonvolatile semiconductor memory device comprises a memory cell array, a control circuit, a current limiting circuit and a current suppression circuit. The memory cell array has a first line, a second line, and a memory cell arranged therein, the memory cell being connected between the first line and the second line and including a variable resistance element. The control circuit is configured to apply, via the first line and the second line, a voltage required in operation of the memory cell. The current limiting circuit is connected to the first line and configured to limit a current flowing in the memory cell to a certain limit value. The current suppression circuit is configured connectable to the second line and configured to suppress a current flowing in the second line according to a kind of operation on the memory cell.

Nonvolatile semiconductor memory device operating stably and method of control therein

According to one embodiment, a semiconductor memory device includes a plurality of first interconnects which extend in a first direction and are arranged in a second direction perpendicular to the first direction, a plurality of second interconnects which extend in the second direction and are arranged in the first direction, and a plurality of first storage modules which are formed in regions where the first interconnects and the second interconnects cross. The semiconductor memory device further comprises a first interconnect control module which supplies a voltage to the first interconnects, detects a first current flowing in the first interconnects, and outputs a first voltage corresponding to the first current, a reference voltage generator module which generates a second voltage based on a second current, and a regulator which generates a third voltage based on the first voltage and the second voltage.

Semiconductor device and method for controlling the same

According to one embodiment, a semiconductor memory device includes a plurality of first interconnects which extend in a first direction and are arranged in a second direction perpendicular to the first direction, a plurality of second interconnects which extend in the second direction and are arranged in the first direction, and memory cells formed in regions where the first and the second interconnects cross. The semiconductor memory device further includes a plurality of first drivers which apply voltages to the first interconnects, respectively, and a second driver which applies a voltage to the first drivers.

According to one embodiment, a control unit multiple-selects a first line for every N lines from a plurality of first lines. N is an integer greater than or equal to one. The control unit sets the multiple-selected first lines to a selection potential, and fixes potentials of non-selected first lines at least adjacent to the multiple-selected first lines at a first timing. The control unit causes the multiple-selected first lines to be in a floating state at a second timing after the first timing. The control unit selects one second line from the plurality of second lines and sets the one second line to a forming potential at a third timing after the second timing.

Non-volatile semiconductor storage device and forming method

A nonvolatile semiconductor memory device according to an embodiment includes a memory cell array configured by plural memory cells each including a variable resistor and each provided between first and second lines. A control circuit applies to a memory cell through the first and second lines a writing voltage for writing data or a reading voltage for reading data. A sense amplifier circuit senses data retained in a memory cell based on a current flowing through the first line. In a data writing operation, the control circuit applies a writing voltage to each of n number of memory cells configuring one unit such that the memory cells may be supplied with different resistance values. In a data reading operation, the sense amplifier circuit compares level relationship of the resistance values of n number of memory cells configuring one unit and reads out n! patterns of data from the one unit.

Nonvolatile semiconductor memory device

According to one embodiment, a semiconductor storage device includes a memory cell array and a control circuit. The memory cell array has memory cells arranged therein at respective intersections between a plurality of first wirings and a plurality of second wirings. Each of the memory cells has a variable resistance element. The control circuit is configured to apply a voltage to a selected one of the first wirings and to a selected one of the second wirings. The control circuit includes a plurality of charge pump circuits and a plurality of clock oscillator circuits. The charge pump circuits generate a voltage applied to the first and second wirings. Each of the clock oscillator circuits is configured to supply a clock signal to a certain number of the charge pump circuits to control the timing of operation thereof. The clock oscillator circuits are configured to output clock signals at different frequencies.

Semiconductor storage device including plural clock oscillator circuits operating at different frequencies

A memory cell array includes a memory cell having a variable resistance element and disposed between first and second wirings. A control circuit provides a selected first wiring with a first voltage and provide a selected second wiring with a second voltage having a lower voltage value than the first voltage. A current limitation circuit controls a cell current below a first current. It includes a first current generation circuit for storing a cell current at a first point of time and generating a first current of &#x3b1; times the stored cell current. It also includes a second current generation circuit for generating a second current of (&#x3b2;/&#x3b1;) times the cell current at a second point of time. A determination circuit outputs a control signal when the second current exceeds the stored current. The first current generation circuit newly stores a stored current according to the control signal.

Non-volatile semiconductor memory device

A semiconductor storage device includes a memory cell array including memory cells arranged at respective intersections between first wirings and second wirings. Each of the memory cells includes a rectifier element and a variable resistance element connected in series. A control circuit is configured to apply a first voltage to a selected first wiring and a second voltage lower than the first voltage to a selected second wiring so that a certain potential difference is applied to a selected memory cell positioned at an intersection between the selected first wiring and the selected second wiring. The control circuit performs a concurrent read operation to perform a read operation from plural memory cells concurrently by applying the first voltage to a plurality of the first wirings concurrently. It is possible to switch the number of the first wirings to be applied with the first voltage concurrently in the concurrent read operation.

Non-volatile semiconductor storage device with concurrent read operation

According to one embodiment, a semiconductor storage device includes a three-dimensional memory cell array, write drivers, and a program voltage control circuit. In the three-dimensional memory cell array, memory cells are three-dimensionally arranged. The write drivers are arranged to be distributed under the three-dimensional memory cell array and apply a program voltage to the memory cells during writing in the memory cells. The program voltage control circuit is arranged around the three-dimensional memory cell array and performs control for making the write drivers to generate the program voltage.

Three dimensional semiconductor storage device having write drivers under a three dimensional memory cell array

A semiconductor memory device in accordance with an embodiment includes: a memory cell array having memory cells disposed at respective intersections of first lines and second lines; and a control circuit configured to apply a first pulse voltage multiple times to selected one of the first lines and selected one of the second lines, such that a certain potential difference is applied to a selected memory cell thereby causing transition of a resistance state. The control circuit is configured to, when the selected memory cell is not caused to undergo transition of the resistance state even after application of the first pulse voltage a certain number of times, execute a rescue operation where a second pulse voltage is applied to the selected memory cell subsequent to application of the first pulse voltage, the second pulse voltage having a pulse width longer than that of the first pulse voltage.

Growing community of inventors

Tokyo, Japan

Takahiko Sasaki