Patents by Inventor Takeshi Hioka

Takeshi Hioka has filed for patents to protect the following inventions. This listing includes patent applications that are pending as well as patents that have already been granted by the United States Patent and Trademark Office (USPTO).

  • Publication number: 20240153562
    Abstract: A semiconductor memory device includes: a first wiring; a first memory transistor; a first transistor; a second memory transistor; a second transistor; a second wiring connected to a gate electrode of the first memory transistor; a third wiring; a first gate wiring connected to a gate electrode of the first transistor; a second gate wiring connected to a gate electrode of the second transistor; and a control circuit configured to execute an erase operation that selects the first or the second memory transistor. The control circuit controls a voltage of the first gate wiring to become larger than a voltage of the second wiring and controls a voltage of the second gate wiring to become larger than the voltage of the first gate wiring in the erase operation performed with the first memory transistor selected.
    Type: Application
    Filed: January 19, 2024
    Publication date: May 9, 2024
    Applicant: KIOXIA CORPORATION
    Inventor: Takeshi HIOKA
  • Patent number: 11978508
    Abstract: According to one embodiment, a semiconductor memory device includes a memory cell, a word line, a bit line, a first transistor, a second transistor and a driver. The word line is electrically coupled to a gate of the memory cell. The bit line is electrically coupled to one end of the memory cell. The first transistor includes a first gate electrically coupled to the bit line. The second transistor is coupled to a first end of the first transistor. The driver is configured to apply a voltage to the first gate of the first transistor. In a read operation, the driver varies a voltage to be applied to the first gate of the first transistor based on a read voltage applied to the word line.
    Type: Grant
    Filed: November 11, 2022
    Date of Patent: May 7, 2024
    Assignee: Kioxia Corporation
    Inventors: Kosuke Yanagidaira, Hiroshi Tsubouchi, Takeshi Hioka
  • Publication number: 20240087656
    Abstract: A semiconductor memory device includes a first memory cell transistor, a first bit line electrically coupled to the first memory cell transistor, a first sense amplifier, and a first latch circuit. The first sense amplifier includes a first node coupled to the first bit line, a first transistor including one end electrically coupled to the first latch circuit, a second node coupled to a gate of the first transistor, and a second transistor coupled between the first and second nodes. The second transistor is in an ON state during an operation of transferring a charge from the first bit line to the first and second nodes in accordance with data of the first memory cell transistor. The second transistor is in an OFF state during an operation of transferring data of the second node to the first latch circuit.
    Type: Application
    Filed: June 12, 2023
    Publication date: March 14, 2024
    Applicant: Kioxia Corporation
    Inventors: Katsuaki ISOBE, Takeshi HIOKA, Mario SAKO
  • Patent number: 11894070
    Abstract: According to one embodiment, a semiconductor memory device includes first and second memory cells; a first word line connected to the first and second memory cells; a first bit line connected to the first memory cell; a second bit line connected to the second memory cell; a first sense amplifier connected to the first bit line; a second sense amplifier connected to the second bit line; a voltage generation circuit; and a first row decoder which supplies a voltage to the first word line.
    Type: Grant
    Filed: January 19, 2023
    Date of Patent: February 6, 2024
    Assignee: KIOXIA CORPORATION
    Inventors: Takeshi Hioka, Tsukasa Kobayashi, Koji Kato, Yuki Shimizu, Hiroshi Maejima
  • Publication number: 20230368848
    Abstract: A semiconductor memory device includes first and second memory cell transistors between first and second select transistors, third and fourth memory cell transistors between third and fourth select transistors, a first word line for first and third memory cell transistors, a second word line for second and fourth memory cell transistors, first to fourth selection gate lines respectively for first through fourth select transistors, a bit line, and a source line. During a read operation, while a voltage applied to the second word line is boosted, voltages applied to the first word line and the third and fourth selection gate line are also boosted, after which the voltage applied to the first word line is lowered, and the third and fourth selection gate lines are discharged. After the time the third and fourth selection gate lines are discharged, voltages applied to the bit line and the source line are boosted.
    Type: Application
    Filed: July 7, 2023
    Publication date: November 16, 2023
    Inventor: Takeshi HIOKA
  • Patent number: 11810629
    Abstract: A semiconductor memory device includes a memory cell array including a plurality of memory cells, a word line connected to the plurality of memory cells, a plurality of bit lines connected respectively to the plurality of memory cells, a sense amplifier connected to the plurality of bit lines, and a controller configured to execute a write operation in a plurality of program loops each including a program operation and a verify operation. The sense amplifier is configured to apply a first voltage, a second voltage higher than the first voltage, a third voltage higher than the second voltage, and a fourth voltage higher than the third voltage to first, second, third, and fourth bit lines of the plurality of bit lines, respectively, while a program voltage is applied to the word line in the program operation.
    Type: Grant
    Filed: August 31, 2022
    Date of Patent: November 7, 2023
    Assignee: Kioxia Corporation
    Inventors: Takeshi Hioka, Toshifumi Watanabe
  • Publication number: 20230317184
    Abstract: A semiconductor memory device includes a memory cell array including a plurality of memory cells, a word line connected to the plurality of memory cells, a plurality of bit lines connected respectively to the plurality of memory cells, a sense amplifier connected to the plurality of bit lines, and a controller configured to execute a write operation in a plurality of program loops each including a program operation and a verify operation. The sense amplifier is configured to apply a first voltage, a second voltage higher than the first voltage, a third voltage higher than the second voltage, and a fourth voltage higher than the third voltage to first, second, third, and fourth bit lines of the plurality of bit lines, respectively, while a program voltage is applied to the word line in the program operation.
    Type: Application
    Filed: August 31, 2022
    Publication date: October 5, 2023
    Inventors: Takeshi HIOKA, Toshifumi WATANABE
  • Publication number: 20230290417
    Abstract: A semiconductor storage device includes a plurality of word line layers stacked above one another in a first direction, a memory pillar having a columnar body penetrating the plurality of the word line layers, wherein each portion of the memory pillar intersecting the word line layers functions as a memory cell transistor, a source line layer to which an end of the memory pillar is connected, an acquisition circuit configured to acquire a voltage of the source line layer, and a first adjustment circuit configured to adjust the voltage of the source line layer to a predetermined target voltage based on the acquired voltage. The acquisition circuit includes a dummy pillar having a columnar body penetrating the plurality of word line layers and having an end connected to the source line layer, wherein each portion of the dummy pillar intersecting the word line layers functions as a dummy transistor.
    Type: Application
    Filed: August 31, 2022
    Publication date: September 14, 2023
    Inventor: Takeshi HIOKA
  • Patent number: 11742032
    Abstract: A semiconductor memory device includes first and second memory cell transistors between first and second select transistors, third and fourth memory cell transistors between third and fourth select transistors, a first word line for first and third memory cell transistors, a second word line for second and fourth memory cell transistors, first to fourth selection gate lines respectively for first through fourth select transistors, a bit line, and a source line. During a read operation, while a voltage applied to the second word line is boosted, voltages applied to the first word line and the third and fourth selection gate line are also boosted, after which the voltage applied to the first word line is lowered, and the third and fourth selection gate lines are discharged. After the time the third and fourth selection gate lines are discharged, voltages applied to the bit line and the source line are boosted.
    Type: Grant
    Filed: January 25, 2022
    Date of Patent: August 29, 2023
    Assignee: Kioxia Corporation
    Inventor: Takeshi Hioka
  • Publication number: 20230154547
    Abstract: According to one embodiment, a semiconductor memory device includes first and second memory cells; a first word line connected to the first and second memory cells; a first bit line connected to the first memory cell; a second bit line connected to the second memory cell; a first sense amplifier connected to the first bit line; a second sense amplifier connected to the second bit line; a voltage generation circuit; and a first row decoder which supplies a voltage to the first word line.
    Type: Application
    Filed: January 19, 2023
    Publication date: May 18, 2023
    Applicant: KIOXIA CORPORATION
    Inventors: Takeshi HIOKA, Tsukasa KOBAYASHI, Koji KATO, Yuki SHIMIZU, Hiroshi MAEJIMA
  • Publication number: 20230062330
    Abstract: According to one embodiment, a semiconductor memory device includes a memory cell, a word line, a bit line, a first transistor, a second transistor and a driver. The word line is electrically coupled to a gate of the memory cell. The bit line is electrically coupled to one end of the memory cell. The first transistor includes a first gate electrically coupled to the bit line. The second transistor is coupled to a first end of the first transistor. The driver is configured to apply a voltage to the first gate of the first transistor. In a read operation, the driver varies a voltage to be applied to the first gate of the first transistor based on a read voltage applied to the word line.
    Type: Application
    Filed: November 11, 2022
    Publication date: March 2, 2023
    Applicant: Kioxia Corporation
    Inventors: Kosuke YANAGIDAIRA, Hiroshi TSUBOUCHI, Takeshi HIOKA
  • Patent number: 11594285
    Abstract: According to one embodiment, a semiconductor memory device includes first and second memory cells; a first word line connected to the first and second memory cells; a first bit line connected to the first memory cell; a second bit line connected to the second memory cell; a first sense amplifier connected to the first bit line; a second sense amplifier connected to the second bit line; a voltage generation circuit; and a first row decoder which supplies a voltage to the first word line.
    Type: Grant
    Filed: September 22, 2021
    Date of Patent: February 28, 2023
    Assignee: Kioxia Corporation
    Inventors: Takeshi Hioka, Tsukasa Kobayashi, Koji Kato, Yuki Shimizu, Hiroshi Maejima
  • Patent number: 11527284
    Abstract: According to one embodiment, a semiconductor memory device includes a memory cell, a word line, a bit line, a first transistor, a second transistor and a driver. The word line is electrically coupled to a gate of the memory cell. The bit line is electrically coupled to one end of the memory cell. The first transistor includes a first gate electrically coupled to the bit line. The second transistor is coupled to a first end of the first transistor. The driver is configured to apply a voltage to the first gate of the first transistor. In a read operation, the driver varies a voltage to be applied to the first gate of the first transistor based on a read voltage applied to the word line.
    Type: Grant
    Filed: March 11, 2021
    Date of Patent: December 13, 2022
    Assignee: Kioxia Corporation
    Inventors: Kosuke Yanagidaira, Hiroshi Tsubouchi, Takeshi Hioka
  • Patent number: 11380406
    Abstract: In general, according to one embodiment, an output circuit includes first to third power supply lines, a pad, first to second transistors, and a first circuit. A first end of the first transistor is coupled to the first power supply line. A second end of the first transistor is coupled to the pad. A first end of the second transistor is coupled to the second power supply line. A second end of the second transistor is coupled to the pad. The first circuit is coupled to each of the third power supply line and a gate of the first transistor. In a first case, the first circuit applies a fourth voltage to the gate of the first transistor.
    Type: Grant
    Filed: September 11, 2020
    Date of Patent: July 5, 2022
    Assignee: KIOXIA CORPORATION
    Inventors: Yousuke Hagiwara, Kensuke Yamamoto, Takeshi Hioka, Satoshi Inoue
  • Publication number: 20220148660
    Abstract: A semiconductor memory device includes first and second memory cell transistors between first and second select transistors, third and fourth memory cell transistors between third and fourth select transistors, a first word line for first and third memory cell transistors, a second word line for second and fourth memory cell transistors, first to fourth selection gate lines respectively for first through fourth select transistors, a bit line, and a source line. During a read operation, while a voltage applied to the second word line is boosted, voltages applied to the first word line and the third and fourth selection gate line are also boosted, after which the voltage applied to the first word line is lowered, and the third and fourth selection gate lines are discharged. After the time the third and fourth selection gate lines are discharged, voltages applied to the bit line and the source line are boosted.
    Type: Application
    Filed: January 25, 2022
    Publication date: May 12, 2022
    Inventor: Takeshi HIOKA
  • Patent number: 11302399
    Abstract: A semiconductor storage device includes first and second memory cells, first and second word lines connected to the first and second memory cells, respectively, a bit line connected to the first and second memory cells, and a sense amplifier including a sense node. During a first read, a controller applies a first read voltage to the second word line and determines a read result. During a second read, the controller discharges the sense node for a first time period while applying a second read voltage to the first word line to determine a first read result, and discharges the sense node for a second time period while applying the second read voltage to determine a second read result. The controller determines read data based on the first read result, the second read result, and the read result of the second memory cell.
    Type: Grant
    Filed: August 31, 2020
    Date of Patent: April 12, 2022
    Assignee: KIOXIA CORPORATION
    Inventors: Kosuke Yanagidaira, Takuyo Kodama, Takeshi Hioka
  • Patent number: 11270775
    Abstract: A semiconductor memory device includes first and second memory cell transistors between first and second select transistors, third and fourth memory cell transistors between third and fourth select transistors, a first word line for first and third memory cell transistors, a second word line for second and fourth memory cell transistors, first to fourth selection gate lines respectively for first through fourth select transistors, a bit line, and a source line. During a read operation, while a voltage applied to the second word line is boosted, voltages applied to the first word line and the third and fourth selection gate line are also boosted, after which the voltage applied to the first word line is lowered, and the third and fourth selection gate lines are discharged. After the time the third and fourth selection gate lines are discharged, voltages applied to the bit line and the source line are boosted.
    Type: Grant
    Filed: November 12, 2020
    Date of Patent: March 8, 2022
    Assignee: KIOXIA CORPORATION
    Inventor: Takeshi Hioka
  • Publication number: 20220013181
    Abstract: According to one embodiment, a semiconductor memory device includes first and second memory cells; a first word line connected to the first and second memory cells; a first bit line connected to the first memory cell; a second bit line connected to the second memory cell; a first sense amplifier connected to the first bit line; a second sense amplifier connected to the second bit line; a voltage generation circuit; and a first row decoder which supplies a voltage to the first word line.
    Type: Application
    Filed: September 22, 2021
    Publication date: January 13, 2022
    Applicant: Toshiba Memory Corporation
    Inventors: Takeshi HIOKA, Tsukasa KOBAYASHI, Koji KATO, Yuki SHIMIZU, Hiroshi MAEJIMA
  • Patent number: 11205482
    Abstract: A semiconductor storage device includes a plurality of memory cells connected to each other in series, a plurality of word lines respectively connected to gates of the plurality of memory cells, and a control circuit configured to perform a read operation by applying a first voltage higher than ground voltage to the plurality of word lines during a first time period at the beginning of which each word line is at ground voltage, applying a second voltage lower than the first voltage to a first word line during a second time period subsequent to the first time period, applying a third voltage higher than the second voltage to the first word line during a third time period subsequent to the second time period, and determining data of the memory cells connected to the first word line while all portions of the first word line are at the third voltage.
    Type: Grant
    Filed: March 2, 2020
    Date of Patent: December 21, 2021
    Assignee: KIOXIA CORPORATION
    Inventors: Takeshi Hioka, Koji Kato
  • Patent number: 11189348
    Abstract: A semiconductor memory device includes a first memory cell, a first select transistor between the first memory cell and a source line, a second select transistor between the first memory cell and a bit line, a third select transistor between the source line and the bit line, and a control circuit. During an erase operation, the control circuit is configured to apply a first voltage to the source line, apply a second voltage lower than the first voltage to a gate of the third select transistor while applying the first voltage to the source line to cause a third voltage to be applied to the bit line, and apply a fourth voltage lower than the third voltage to the gate of the second select transistor while the third voltage is applied to the bit line.
    Type: Grant
    Filed: September 1, 2020
    Date of Patent: November 30, 2021
    Assignee: KIOXIA CORPORATION
    Inventors: Takeshi Hioka, Naofumi Abiko, Masaki Unno