Kabushiki Kaisha Toshiba

Kioxia Corporation

Toshiba Memory Corporation

Hidehiro Shiga

Daisaburo Takashima

Masanobu Shirakawa

Takashi Maeda

Rieko Funatsuki

Shinichiro Shiratake

Hiroshi Maejima

Kazutaka Ikegami

Daisuke Hashimoto

Yasuhiro Shimura

Koki Ueno

Kenichi Abe

Keisuke Yonehama

Tomoki Higashi

Yuki Kanamori

Shinichi Oosera

Sumito Ohtsuki

Junichi Kijima

Tomoki Chiba

Koji Hosono

Tokumasa Hara

Masumi Saitoh

Ryu Ogiwara

Atsushi Kawasumi

Takayuki Miyazaki

Shinji Miyano

Jun Deguchi

Masaki Kondo

Daisuke Miyashita

Dai Nakamura

Tomonori Kurosawa

Tetsuya Sunata

Sanad Bushnaq

Keita Kimura

Nobuyuki Momo

Reika Tanaka

Yuya Suzuki

Takumi Fujimori

Reiko Sumi

Shinichi Sasaki

Natsuki Sakaguchi

A memory system for speeding up a read operation in the memory system includes a first pillar, a first string including a first transistor and a first memory cell, a second string including a second transistor and a second memory cell, a first bit line, a first gate line, a first word line, a second gate line, a second word line and a control circuit. When the control circuit executes a read operation with respect to the first memory cell, the control circuit is configured to apply a read voltage to the first word line, apply a voltage turning off the second memory cell regardless of an electric charge stored in the second memory cell to the second word line, apply a voltage turning on the first transistor to the first gate line, and apply a voltage turning on the second transistor to the second gate line.

Memory system

According to an embodiment, a memory system includes: a nonvolatile memory including a plurality of blocks; and a memory controller. The memory controller is configured to: make a comparison between a first erase voltage application accumulated time period and a first erase verify permission time period each corresponding to a first block targeted for erasure; cause the nonvolatile memory to execute a erase voltage application operation in a case where the first erase voltage application accumulated time period is less than the first erase verify permission time period; and cause the nonvolatile memory to execute a erase verify operation in a case where the first erase voltage application accumulated time period is equal to or greater than the first erase verify permission time period.

Memory system for performing an erase voltage application operation and an erase verify operation for a nonvolatile memory

According to one embodiment, in a semiconductor memory device, multiple first memory cells are connected in parallel between a first local bit line and a local source line. Multiple second memory cells are connected in parallel between a second local bit line and the local source line. Each of the multiple first memory cells includes a first cell transistor and a first resistance change element connected in series. Each of the multiple second memory cells includes a second cell transistor and a second resistance change element connected in series. A first selection gate line extends in a second direction across multiple cell blocks arranged in the second direction. A second selection gate line is placed on the opposite side of the first selection gate line with the local source line interposed therebetween. The second selection gate line extends in the second direction across multiple cell blocks arranged in the second direction.

Semiconductor memory device

A control circuit of a semiconductor memory device performs a write operation on a memory cell transistor of the semiconductor memory device by performing a first pulse application operation of lowering a threshold voltage of the memory cell transistor, a precharge operation, and then a second pulse application operation. In the precharge operation, in a state in which first and second select transistors connected to the memory cell transistor are turned on, a bit line connected to the memory cell transistor is charged by applying a ground voltage to a word line connected to a gate of the memory cell transistor and applying a voltage higher than the ground voltage to a source line. In the second pulse application operation, in a state in which the first select transistor is turned on and the second select transistor is turned off, a program voltage is applied to the word line.

A variable resistance non-volatile memory includes a semiconductor substrate, a first electrode line extending in a first direction away from the semiconductor substrate, a second electrode line extending in the first direction parallel to the first electrode line, an insulating film between the first and second electrode lines, a variable resistance film formed on the first electrode line, a low electrical resistance layer formed on the variable resistance film and having a lower electrical resistance than the variable resistance film, a semiconductor film in contact with the low electrical resistance layer and the insulating film, and formed on opposite surfaces of the second electrode line, a gate insulator film extending in the first direction and in contact with the semiconductor film, and a voltage application electrode that extends in a second direction that crosses the first direction, and is in contact with the gate insulator film.

Variable resistance non-volatile memory with a gate insulator film at a same height as a voltage application electrode

According to a certain embodiment, the 3D stacked semiconductor memory includes: a first electrode line extending in a first direction orthogonal to the semiconductor substrate; a second electrode line adjacent to the first electrode line in a second direction orthogonal to the first direction, and extending in the first direction; a first variable resistance film extending in the first direction and in contact with the second electrode line; a first semiconductor film in contact with the first variable resistance film and the first electrode line; a first potential applying electrode extending in the second direction and in contact with a first insulator layer; a second semiconductor film in contact with a second variable resistance film and the first electrode line; and a second potential applying electrode extending in the second direction and in contact with a second insulator layer. The first and second potential applying electrodes are electrically different nodes.

Three dimensional stacked semiconductor memory

A semiconductor memory device includes a driver that, in a write operation, applies a first voltage to a first select gate line, applies a second voltage lower than the first voltage to a second select gate line, applies a third voltage equal to or higher than the first voltage to a first dummy word line on an uppermost layer, applies a fourth voltage different from the third voltage and higher than the second voltage to a second dummy word line on an uppermost layer, applies a fifth voltage equal to or higher than the third voltage to a first dummy word line on a lowermost layer, and applies a sixth voltage different from the fifth voltage and equal to or higher than the fourth voltage to a second dummy word line on a lowermost layer.

A semiconductor storage device includes a memory cell array including a plurality of word line groups and a plurality of blocks corresponding to the plurality of word line groups. Each of word line groups includes a plurality of word lines and each of the blocks includes a plurality of memory cells. The plurality of memory cells of each block are connected to the respective word lines of a corresponding one of the word line groups. The semiconductor storage device includes a row decoder including a plurality of word line group decoders corresponding to the plurality of word line groups, respectively. Each of the plurality of word line group decoders is configured to drive a word line independent from a word line driven in another of the word line groups, when all of the plurality of word line groups are activated in parallel.

Semiconductor storage device

A memory device includes a memory cell array including a select transistor and a plurality of memory cells connected in series, each memory cell including a cell transistor and a variable resistance layer connected in parallel. During a write operation, a voltage setting circuit is controlled to apply a first voltage to a selected word line and a second voltage to non-selected word lines. The time period for applying the first voltage to the selected word line starts later than the time period for applying the second voltage to the non-selected word lines and ends earlier than the time period for applying the second voltage to the non-selected word lines.

Memory device

A nonvolatile memory includes a first memory cell and a second memory cell above the first memory cell. The first memory cell includes a variable resistance layer extending in a first direction, a semiconductor layer extending in the first direction and in contact with the variable resistance layer, an insulator layer extending in the first direction and in contact with the semiconductor layer, and a first voltage applying electrode extending in a second direction and in contact with the insulator layer. The second memory cell includes a second voltage applying electrode in contact with the insulator layer. When a write operation is performed on the first memory cell, a first voltage is applied to the second voltage applying electrode, and when a write operation is performed on the second memory cell, a second voltage, lower than the first voltage, is applied to the first voltage applying electrode.

Variable resistance nonvolatile memory

A semiconductor memory device includes i first word lines connected to the i first memory cells, i second word lines connected to the i second memory cells, a driver capable of supplying voltage to each of the i first word lines and each of the i second word lines, and a logic control circuit controlling both a write operation including a verify operation and a read operation including a verify operation. In the semiconductor memory device, when an order of performing a sense operation for determining whether or not a threshold voltage of the k-th first memory cell has reached a j-th threshold voltage in the verify operation is different from that of in the read operation, a voltage applied to the k-th first word line in the verify operation is different from a voltage applied to the k-th first word line in the read operation.

A nonvolatile semiconductor storage device includes first and second semiconductor layers extending in a first direction and spaced apart in a second direction, first and second bit lines extending in the second direction and respectively arranged on opposite sides of the semiconductor layers in the first direction, first and second source lines extending in a third direction and respectively arranged on opposite sides of the semiconductor layers in the first direction, a first memory string including first and second select transistors connected to the first bit line and the first source line, respectively, a second memory string including third and fourth select transistors connected to the second bit line and the second source line, respectively, a first select gate line connected to gates of the first and fourth select transistors, and a second select gate line connected to gates of the second and third select transistors.

Nonvolatile semiconductor storage device having memory strings and bit lines on opposite sides of the memory strings

A semiconductor storage device includes a first word line, a second word line provided in the same layer with the first word line and configured to be controlled independently from the first word line, a plurality of memory pillars between the first word line and the second word line, each of the plurality of memory pillars including a first memory cell facing to the first word line and a second memory cell facing to the second word line, the plurality of memory pillars being arranged in a first direction and a second direction intersecting to the first direction and a control circuit. The control circuit is configured to perform a write operation to the second memory cell included in the plurality of memory pillars after performing a write operation to the first memory cell included in each of the plurality of memory pillars.

Semiconductor storage device having reduced threshold distribution interference

A semiconductor storage device includes a semiconductor pillar, a first string having first memory cells connected in series, first word lines connected to the first memory cells, a second string having second memory cells connected in series, and second word lines connected to the second memory cells. Each of the first memory cells faces, and shares a channel in the semiconductor pillar with, one of the second memory cells. When reading data of the k-th first memory cell, a voltage of the first word line connected to the k-th first memory cell reaches a first voltage at a first timing, and a voltage of the second word line connected to at least one of the second memory cells other than the k-th second memory cell in the second string facing the k-th first memory cell reaches the first voltage at a second timing that is later than the first timing.

Semiconductor storage device having first and second memory strings formed on opposite sides of the same pillar and method of performing a read operation therein

According to one embodiment, a memory device includes: a third layer between first and a second layers above a substrate; a pillar being adjacent to the first to third layers and including a ferroelectric layer; a memory cell between the third layer and the pillar; and a circuit which executes a first operation for a programming, a second operation for an erasing using a first voltage, and a third operation of applying a second voltage between the third layer and the pillar. The first voltage has a first potential difference, the second voltage has a second potential difference smaller than the first potential difference. A potential of the third conductive layer is lower than a potential of the pillar in each of the first and second voltages. The third operation is executed between the first operation and the second operation.

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Yokohama, Japan

Hidehiro Shiga