Patents by Inventor Tomoki Higashi

Tomoki Higashi 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).

  • Patent number: 11923015
    Abstract: According to one embodiment, a semiconductor storage device includes strings each with a first select transistor, memory cell transistors, and a second select transistor connected in series. Word lines are provided, each connected to memory cell transistors in a same position across the strings. A bit line is connected in common to a first end of each of the strings. A source line is connected in common to a second end of each of the strings. A control circuit is configured to perform an erase operation on strings. The control circuit adjusts, for each of the strings, either an application time of a first voltage applied to a gate of the first select transistor of the respective string in the erase operation or a voltage level of the first voltage applied to the gate of the first select transistor of the respective string in the erase operation.
    Type: Grant
    Filed: February 28, 2022
    Date of Patent: March 5, 2024
    Assignee: Kioxia Corporation
    Inventors: Shinichi Oosera, Sumito Ohtsuki, Tomoki Higashi, Yuki Soh
  • Publication number: 20230087334
    Abstract: According to one embodiment, a semiconductor storage device includes strings each with a first select transistor, memory cell transistors, and a second select transistor connected in series. Word lines are provided, each connected to memory cell transistors in a same position across the strings. A bit line is connected in common to a first end of each of the strings. A source line is connected in common to a second end of each of the strings. A control circuit is configured to perform an erase operation on strings. The control circuit adjusts, for each of the strings, either an application time of a first voltage applied to a gate of the first select transistor of the respective string in the erase operation or a voltage level of the first voltage applied to the gate of the first select transistor of the respective string in the erase operation.
    Type: Application
    Filed: February 28, 2022
    Publication date: March 23, 2023
    Inventors: Shinichi OOSERA, Sumito Ohtsuki, Tomoki Higashi, Yuki Soh
  • Patent number: 10803950
    Abstract: According to one embodiment, a memory controller transmits a first instruction to a memory device. The memory device includes cell transistors; word lines coupled to gates of the cell transistors; a first data latch; and a second latch. The first instruction instructs application of a positive voltage to one of the word lines. The memory controller transmits a second instruction after the transmission of the first instruction and before transmitting a third instruction. The third instruction instructs output of data from the memory device. The second instruction is different from the third instruction and a fourth instruction instructing copy of data from the first data latch to the second data latch.
    Type: Grant
    Filed: May 23, 2019
    Date of Patent: October 13, 2020
    Assignee: Toshiba Memory Corporation
    Inventors: Yasuhiro Shimura, Tomoki Higashi, Sumito Ohtsuki, Junichi Kijima, Keisuke Yonehama, Shinichi Oosera, Yuki Kanamori, Hidehiro Shiga, Koki Ueno
  • Publication number: 20190279716
    Abstract: According to one embodiment, a memory controller transmits a first instruction to a memory device. The memory device includes cell transistors; word lines coupled to gates of the cell transistors; a first data latch; and a second latch. The first instruction instructs application of a positive voltage to one of the word lines. The memory controller transmits a second instruction after the transmission of the first instruction and before transmitting a third instruction. The third instruction instructs output of data from the memory device. The second instruction is different from the third instruction and a fourth instruction instructing copy of data from the first data latch to the second data latch.
    Type: Application
    Filed: May 23, 2019
    Publication date: September 12, 2019
    Applicant: Toshiba Memory Corporation
    Inventors: Yasuhiro Shimura, Tomoki Higashi, Sumito Ohtsuki, Junichi Kijima, Keisuke Yonehama, Shinichi Oosera, Yuki Kanamori, Hidehiro Shiga, Koki Ueno
  • Patent number: 10347338
    Abstract: According to one embodiment, a memory controller transmits a first instruction to a memory device. The memory device includes cell transistors; word lines coupled to gates of the cell transistors; a first data latch; and a second latch. The first instruction instructs application of a positive voltage to one of the word lines. The memory controller transmits a second instruction after the transmission of the first instruction and before transmitting a third instruction. The third instruction instructs output of data from the memory device. The second instruction is different from the third instruction and a fourth instruction instructing copy of data from the first data latch to the second data latch.
    Type: Grant
    Filed: September 8, 2017
    Date of Patent: July 9, 2019
    Assignee: Toshiba Memory Corporation
    Inventors: Yasuhiro Shimura, Tomoki Higashi, Sumito Ohtsuki, Junichi Kijima, Keisuke Yonehama, Shinichi Oosera, Yuki Kanamori, Hidehiro Shiga, Koki Ueno
  • Patent number: 10255979
    Abstract: According to one embodiment, a semiconductor memory device includes: a memory cell array including a plurality of memory strings, each of the memory strings including a plurality of memory cells connected in series; a plurality of word lines commonly connected to the memory strings and connected to the memory cells; and a control circuit which executes a write operation including a plurality of program loops, each of the program loops including a program operation and a verify operation. When a suspend command for instructing an operation suspend is externally received during execution of the program operation, the control circuit executes a dummy read operation in which the word lines are applied with a voltage after the program operation, and enters into a suspend mode after the dummy read operation.
    Type: Grant
    Filed: March 9, 2018
    Date of Patent: April 9, 2019
    Assignee: Toshiba Memory Corporation
    Inventors: Yasuhiro Shimura, Shinichi Oosera, Junichi Kijima, Tomoki Higashi, Sumito Ohtsuki, Tomohiro Oda, Keisuke Yonehama
  • Publication number: 20190088342
    Abstract: According to one embodiment, a semiconductor memory device includes: a memory cell array including a plurality of memory strings, each of the memory strings including a plurality of memory cells connected in series; a plurality of word lines commonly connected to the memory strings and connected to the memory cells; and a control circuit which executes a write operation including a plurality of program loops, each of the program loops including a program operation and a verify operation. When a suspend command for instructing an operation suspend is externally received during execution of the program operation, the control circuit executes a dummy read operation in which the word lines are applied with a voltage after the program operation, and enters into a suspend mode after the dummy read operation.
    Type: Application
    Filed: March 9, 2018
    Publication date: March 21, 2019
    Applicant: Toshiba Memory Corporation
    Inventors: Yasuhiro SHIMURA, Shinichi Oosera, Junichi Kijima, Tomoki Higashi, Sumito Ohtsuki, Tomohiro Oda, Keisuke Yonehama
  • Publication number: 20180268906
    Abstract: According to one embodiment, a memory controller transmits a first instruction to a memory device. The memory device includes cell transistors; word lines coupled to gates of the cell transistors; a first data latch; and a second latch. The first instruction instructs application of a positive voltage to one of the word lines. The memory controller transmits a second instruction after the transmission of the first instruction and before transmitting a third instruction. The third instruction instructs output of data from the memory device. The second instruction is different from the third instruction and a fourth instruction instructing copy of data from the first data latch to the second data latch.
    Type: Application
    Filed: September 8, 2017
    Publication date: September 20, 2018
    Applicant: Toshiba Memory Corporation
    Inventors: Yasuhiro SHIMURA, Tomoki HIGASHI, Sumito OHTSUKI, Junichi KIJIMA, Keisuke YONEHAMA, Shinichi OOSERA, Yuki KANAMORI, Hidehiro SHIGA, Koki UENO
  • Publication number: 20160240261
    Abstract: A nonvolatile semiconductor memory device comprises a plurality of memory blocks, each including a plurality of cell units and each configured as a unit of execution of an erase operation. Each of the cell units comprises a memory string, a first transistor, a second transistor, and a diode. The first transistor has one end connected to one end of the memory string. The second transistor is provided between the other end of the memory string and a second line. The diode is provided between the other end of the first transistor and a first line. The diode comprises a second semiconductor layer of a first conductivity type and a third semiconductor layer of a second conductivity type.
    Type: Application
    Filed: April 25, 2016
    Publication date: August 18, 2016
    Applicant: Kabushiki Kaisha Toshiba
    Inventors: Hitoshi IWAI, Tomoki HIGASHI, Shinichi OOSERA
  • Publication number: 20140313829
    Abstract: A nonvolatile semiconductor memory device comprises a plurality of memory blocks, each including a plurality of cell units and each configured as a unit of execution of an erase operation. Each of the cell units comprises a memory string, a first transistor, a second transistor, and a diode. The first transistor has one end connected to one end of the memory string. The second transistor is provided between the other end of the memory string and a second line. The diode is provided between the other end of the first transistor and a first line. The diode comprises a second semiconductor layer of a first conductivity type and a third semiconductor layer of a second conductivity type.
    Type: Application
    Filed: July 1, 2014
    Publication date: October 23, 2014
    Applicant: Kabushiki Kaisha Toshiba
    Inventors: Hitoshi IWAI, Tomoki HIGASHI, Shinichi OOSERA
  • Patent number: 8804427
    Abstract: A nonvolatile semiconductor memory device comprises a plurality of memory blocks, each including a plurality of cell units and each configured as a unit of execution of an erase operation. Each of the cell units comprises a memory string, a first transistor, a second transistor, and a diode. The first transistor has one end connected to one end of the memory string. The second transistor is provided between the other end of the memory string and a second line. The diode is provided between the other end of the first transistor and a first line. The diode comprises a second semiconductor layer of a first conductivity type and a third semiconductor layer of a second conductivity type.
    Type: Grant
    Filed: December 2, 2013
    Date of Patent: August 12, 2014
    Assignee: Kabushiki Kaisha Toshiba
    Inventors: Hitoshi Iwai, Tomoki Higashi, Shinichi Oosera
  • Patent number: 8750017
    Abstract: According to one embodiment, a resistance-change memory includes bit lines, word lines, a memory cell array including memory cells arranged at intersections between the bit lines and the word lines, each of the memory cells including a variable-resistance element and a diode, a control circuit configured to apply a reverse bias to the diode, and to write data to a selected memory cell, and a current limiting circuit configured to limit a current flowing to the selected memory cell in a write. The current limiting circuit controls the current flowing to the selected memory cell not to exceed a second compliance current obtained by adding a leakage current from an unselected memory cell to a predetermined first compliance current.
    Type: Grant
    Filed: January 26, 2012
    Date of Patent: June 10, 2014
    Assignee: Kabushiki Kaisha Toshiba
    Inventors: Mizuki Kaneko, Tomoki Higashi, Tomonori Kurosawa
  • Publication number: 20140085991
    Abstract: A nonvolatile semiconductor memory device comprises a plurality of memory blocks, each including a plurality of cell units and each configured as a unit of execution of an erase operation. Each of the cell units comprises a memory string, a first transistor, a second transistor, and a diode. The first transistor has one end connected to one end of the memory string. The second transistor is provided between the other end of the memory string and a second line. The diode is provided between the other end of the first transistor and a first line. The diode comprises a second semiconductor layer of a first conductivity type and a third semiconductor layer of a second conductivity type.
    Type: Application
    Filed: December 2, 2013
    Publication date: March 27, 2014
    Applicant: Kabushiki Kaisha Toshiba
    Inventors: Hitoshi IWAI, Tomoki HIGASHI, Shinichi OOSERA
  • Patent number: 8659947
    Abstract: A nonvolatile semiconductor memory device comprises a plurality of memory blocks, each including a plurality of cell units and each configured as a unit of execution of an erase operation. Each of the cell units comprises a memory string, a first transistor, a second transistor, and a diode. The first transistor has one end connected to one end of the memory string. The second transistor is provided between the other end of the memory string and a second line. The diode is provided between the other end of the first transistor and a first line. The diode comprises a second semiconductor layer of a first conductivity type and a third semiconductor layer of a second conductivity type.
    Type: Grant
    Filed: April 25, 2013
    Date of Patent: February 25, 2014
    Assignee: Kabushiki Kaisha Toshiba
    Inventors: Hitoshi Iwai, Tomoki Higashi, Shinichi Oosera
  • Publication number: 20130229876
    Abstract: A nonvolatile semiconductor memory device comprises a plurality of memory blocks, each including a plurality of cell units and each configured as a unit of execution of an erase operation. Each of the cell units comprises a memory string, a first transistor, a second transistor, and a diode. The first transistor has one end connected to one end of the memory string. The second transistor is provided between the other end of the memory string and a second line. The diode is provided between the other end of the first transistor and a first line. The diode comprises a second semiconductor layer of a first conductivity type and a third semiconductor layer of a second conductivity type.
    Type: Application
    Filed: April 25, 2013
    Publication date: September 5, 2013
    Applicant: Kabushiki Kaisha Toshiba
    Inventors: Hitoshi IWAI, Tomoki Higashi, Shinichi Oosera
  • Patent number: 8493796
    Abstract: A nonvolatile semiconductor memory device according to an embodiment of the present invention includes: a memory cell array having a plurality of memory cells arranged therein, each of the memory cells having a charge storage layer and a control electrode; and a control unit configured to execute a write cycle multiple times, the write cycle including a write operation and a write verify operation, the write operation being an operation for applying a write pulse voltage multiple times to the control electrode selected for data write, and the write verify operation being an operation for determining whether data write is completed or not. During one time of the write operation, the control unit makes a voltage value of a finally applied write pulse voltage larger than a voltage value of an initially applied write pulse voltage.
    Type: Grant
    Filed: September 22, 2011
    Date of Patent: July 23, 2013
    Assignee: Kabushiki Kaisha Toshiba
    Inventors: Tomoki Higashi, Kazumi Tanimoto
  • Publication number: 20120243294
    Abstract: According to one embodiment, a resistance-change memory includes bit lines, word lines, a memory cell array including memory cells arranged at intersections between the bit lines and the word lines, each of the memory cells including a variable-resistance element and a diode, a control circuit configured to apply a reverse bias to the diode, and to write data to a selected memory cell, and a current limiting circuit configured to limit a current flowing to the selected memory cell in a write. The current limiting circuit controls the current flowing to the selected memory cell not to exceed a second compliance current obtained by adding a leakage current from an unselected memory cell to a predetermined first compliance current.
    Type: Application
    Filed: January 26, 2012
    Publication date: September 27, 2012
    Inventors: Mizuki Kaneko, Tomoki Higashi, Tomonori Kurosawa
  • Publication number: 20120134212
    Abstract: A nonvolatile semiconductor memory device according to an embodiment of the present invention includes: a memory cell array having a plurality of memory cells arranged therein, each of the memory cells having a charge storage layer and a control electrode; and a control unit configured to execute a write cycle multiple times, the write cycle including a write operation and a write verify operation, the write operation being an operation for applying a write pulse voltage multiple times to the control electrode selected for data write, and the write verify operation being an operation for determining whether data write is completed or not. During one time of the write operation, the control unit makes a voltage value of a finally applied write pulse voltage larger than a voltage value of an initially applied write pulse voltage.
    Type: Application
    Filed: September 22, 2011
    Publication date: May 31, 2012
    Applicant: Kabushiki Kaisha Toshiba
    Inventors: TOMOKI HIGASHI, KAZUMI TANIMOTO
  • Publication number: 20120069660
    Abstract: A nonvolatile semiconductor memory device comprises a plurality of memory blocks, each including a plurality of cell units and each configured as a unit of execution of an erase operation. Each of the cell units comprises a memory string, a first transistor, a second transistor, and a diode. The first transistor has one end connected to one end of the memory string. The second transistor is provided between the other end of the memory string and a second line. The diode is provided between the other end of the first transistor and a first line. The diode comprises a second semiconductor layer of a first conductivity type and a third semiconductor layer of a second conductivity type.
    Type: Application
    Filed: March 7, 2011
    Publication date: March 22, 2012
    Applicant: Kabushiki Kaisha Toshiba
    Inventors: Hitoshi IWAI, Tomoki HIGASHI, Shinichi OOSERA
  • Publication number: 20110069556
    Abstract: A NAND flash memory has a memory cell transistor, the memory cell transistor including a charge storage layer formed over a well of a semiconductor substrate surface via a first insulation film and insulated from surroundings, and a control gate provided over the charge storage layer via a second insulation film, the memory cell transistor storing information according to a threshold voltage which depends on a charge quantity retained by the charge storage layer; and a control circuit which controls operation of the memory cell transistor by controlling a voltage applied to the control gate and a voltage applied to the well.
    Type: Application
    Filed: August 24, 2010
    Publication date: March 24, 2011
    Applicant: Kabushiki Kaisha Toshiba
    Inventors: Tomoki HIGASHI, Kazumi Tanimoto