Patents by Inventor Eietsu Takahashi
Eietsu Takahashi 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: 20240347113Abstract: A nonvolatile semiconductor memory device according to one embodiment of the present invention includes: a memory cell array and a control circuit. The control circuit executes a first reading operation and a second reading operation. The first reading operation is an operation of reading a threshold voltage set in the selected memory cell by setting a voltage between a control gate electrode and source of the selected memory cell to a first value. The second reading operation is an operation of reading a threshold voltage set in the selected memory cell by setting a voltage between the control gate electrode and source of the selected memory cell to a second value lower than the first value. When executing the second reading operation, the control circuit keeps a voltage of the control gate electrode of the selected memory cell to 0 or a positive value.Type: ApplicationFiled: June 25, 2024Publication date: October 17, 2024Applicant: KIOXIA CORPORATIONInventors: Yasuhiro SHIINO, Eietsu TAKAHASHI, Koki UENO
-
Patent number: 12068040Abstract: A nonvolatile semiconductor memory device according to one embodiment of the present invention includes: a memory cell array and a control circuit. The control circuit executes a first reading operation and a second reading operation. The first reading operation is an operation of reading a threshold voltage set in the selected memory cell by setting a voltage between a control gate electrode and source of the selected memory cell to a first value. The second reading operation is an operation of reading a threshold voltage set in the selected memory cell by setting a voltage between the control gate electrode and source of the selected memory cell to a second value lower than the first value. When executing the second reading operation, the control circuit keeps a voltage of the control gate electrode of the selected memory cell to 0 or a positive value.Type: GrantFiled: September 15, 2023Date of Patent: August 20, 2024Assignee: KIOXIA CORPORATIONInventors: Yasuhiro Shiino, Eietsu Takahashi, Koki Ueno
-
Publication number: 20240153560Abstract: A nonvolatile semiconductor memory device includes a control circuit configured to control a soft program operation of setting nonvolatile memory cells to a first threshold voltage distribution state of the nonvolatile memory cells. When a characteristic of the nonvolatile memory cells is in a first state, the control circuit executes the soft program operation by applying a first voltage for setting the nonvolatile memory cells to the first threshold voltage distribution state to first word lines, and applying a second voltage higher than the first voltage to a second word line. When the characteristic of the nonvolatile memory cells is in a second state, the control circuit executes the soft program operation by applying a third voltage equal to or lower than the first voltage to the first word lines and applying a fourth voltage lower than the second voltage to the second word line.Type: ApplicationFiled: January 17, 2024Publication date: May 9, 2024Applicant: KIOXIA CORPORATIONInventors: Yasuhiro SHIINO, Eietsu TAKAHASHI
-
Publication number: 20240105272Abstract: A semiconductor memory device includes: a first bit line connected to a first string including memory cell transistors; a second bit line connected to a second string including memory cell transistors; a source line connected to the first string and the second string; a word line connected to gates of the memory cell transistors in same rows of the first and strings; a voltage generation circuit configured to apply a first voltage to the first bit line according to a first target level, apply a second voltage to the second bit line according to a second target level, and apply a third voltage to the source line; and a row decoder configured to apply a fourth voltage to the word line to which a first memory cell transistor of the first string and a second memory cell transistor of the second string are connected during a verification operation.Type: ApplicationFiled: September 1, 2023Publication date: March 28, 2024Inventor: Eietsu TAKAHASHI
-
Patent number: 11915756Abstract: A nonvolatile semiconductor memory device includes a control circuit configured to control a soft program operation of setting nonvolatile memory cells to a first threshold voltage distribution state of the nonvolatile memory cells. When a characteristic of the nonvolatile memory cells is in a first state, the control circuit executes the soft program operation by applying a first voltage for setting the nonvolatile memory cells to the first threshold voltage distribution state to first word lines, and applying a second voltage higher than the first voltage to a second word line. When the characteristic of the nonvolatile memory cells is in a second state, the control circuit executes the soft program operation by applying a third voltage equal to or lower than the first voltage to the first word lines and applying a fourth voltage lower than the second voltage to the second word line.Type: GrantFiled: May 2, 2022Date of Patent: February 27, 2024Assignee: KIOXIA CORPORATIONInventors: Yasuhiro Shiino, Eietsu Takahashi
-
Publication number: 20240005999Abstract: A nonvolatile semiconductor memory device according to one embodiment of the present invention includes: a memory cell array and a control circuit. The control circuit executes a first reading operation and a second reading operation. The first reading operation is an operation of reading a threshold voltage set in the selected memory cell by setting a voltage between a control gate electrode and source of the selected memory cell to a first value. The second reading operation is an operation of reading a threshold voltage set in the selected memory cell by setting a voltage between the control gate electrode and source of the selected memory cell to a second value lower than the first value. When executing the second reading operation, the control circuit keeps a voltage of the control gate electrode of the selected memory cell to 0 or a positive value.Type: ApplicationFiled: September 15, 2023Publication date: January 4, 2024Applicant: KIOXIA CORPORATIONInventors: Yasuhiro SHIINO, Eietsu TAKAHASHI, Koki UENO
-
Patent number: 11817155Abstract: A nonvolatile semiconductor memory device according to one embodiment of the present invention includes: a memory cell array and a control circuit. The control circuit executes a first reading operation and a second reading operation. The first reading operation is an operation of reading a threshold voltage set in the selected memory cell by setting a voltage between a control gate electrode and source of the selected memory cell to a first value. The second reading operation is an operation of reading a threshold voltage set in the selected memory cell by setting a voltage between the control gate electrode and source of the selected memory cell to a second value lower than the first value. When executing the second reading operation, the control circuit keeps a voltage of the control gate electrode of the selected memory cell to 0 or a positive value.Type: GrantFiled: February 23, 2023Date of Patent: November 14, 2023Assignee: KIOXIA CORPORATIONInventors: Yasuhiro Shiino, Eietsu Takahashi, Koki Ueno
-
Publication number: 20230197167Abstract: A nonvolatile semiconductor memory device according to one embodiment of the present invention includes: a memory cell array and a control circuit. The control circuit executes a first reading operation and a second reading operation. The first reading operation is an operation of reading a threshold voltage set in the selected memory cell by setting a voltage between a control gate electrode and source of the selected memory cell to a first value. The second reading operation is an operation of reading a threshold voltage set in the selected memory cell by setting a voltage between the control gate electrode and source of the selected memory cell to a second value lower than the first value. When executing the second reading operation, the control circuit keeps a voltage of the control gate electrode of the selected memory cell to 0 or a positive value.Type: ApplicationFiled: February 23, 2023Publication date: June 22, 2023Applicant: KIOXIA CORPORATIONInventors: Yasuhiro SHIINO, Eietsu TAKAHASHI, Koki UENO
-
Patent number: 11621041Abstract: A nonvolatile semiconductor memory device according to one embodiment of the present invention includes: a memory cell array and a control circuit. The control circuit executes a first reading operation and a second reading operation. The first reading operation is an operation of reading a threshold voltage set in the selected memory cell by setting a voltage between a control gate electrode and source of the selected memory cell to a first value. The second reading operation is an operation of reading a threshold voltage set in the selected memory cell by setting a voltage between the control gate electrode and source of the selected memory cell to a second value lower than the first value. When executing the second reading operation, the control circuit keeps a voltage of the control gate electrode of the selected memory cell to 0 or a positive value.Type: GrantFiled: March 31, 2021Date of Patent: April 4, 2023Assignee: Kioxia CorporationInventors: Yasuhiro Shiino, Eietsu Takahashi, Koki Ueno
-
Patent number: 11486767Abstract: A semiconductor storage device includes a memory cell and a control circuit configured to, upon receipt of a command, acquire a first temperature measured by a temperature sensor, and perform an operation corresponding to the command using a parameter corrected based on temperature. When the first temperature is within a predetermined range with respect to a second temperature measured before the command is received, the parameter is corrected using the second temperature. When the first temperature is outside the predetermined range, the parameter is corrected using the first temperature.Type: GrantFiled: March 1, 2021Date of Patent: November 1, 2022Assignee: KIOXIA CORPORATIONInventors: Keisuke Terada, Eietsu Takahashi
-
Publication number: 20220262439Abstract: A nonvolatile semiconductor memory device includes a control circuit configured to control a soft program operation of setting nonvolatile memory cells to a first threshold voltage distribution state of the nonvolatile memory cells. When a characteristic of the nonvolatile memory cells is in a first state, the control circuit executes the soft program operation by applying a first voltage for setting the nonvolatile memory cells to the first threshold voltage distribution state to first word lines, and applying a second voltage higher than the first voltage to a second word line. When the characteristic of the nonvolatile memory cells is in a second state, the control circuit executes the soft program operation by applying a third voltage equal to or lower than the first voltage to the first word lines and applying a fourth voltage lower than the second voltage to the second word line.Type: ApplicationFiled: May 2, 2022Publication date: August 18, 2022Applicant: KIOXIA CORPORATIONInventors: Yasuhiro SHIINO, Eietsu TAKAHASHI
-
Patent number: 11355193Abstract: A nonvolatile semiconductor memory device includes a control circuit configured to control a soft program operation of setting nonvolatile memory cells to a first threshold voltage distribution state of the nonvolatile memory cells. When a characteristic of the nonvolatile memory cells is in a first state, the control circuit executes the soft program operation by applying a first voltage for setting the nonvolatile memory cells to the first threshold voltage distribution state to first word lines, and applying a second voltage higher than the first voltage to a second word line. When the characteristic of the nonvolatile memory cells is in a second state, the control circuit executes the soft program operation by applying a third voltage equal to or lower than the first voltage to the first word lines and applying a fourth voltage lower than the second voltage to the second word line.Type: GrantFiled: October 6, 2020Date of Patent: June 7, 2022Assignee: KIOXIA CORPORATIONInventors: Yasuhiro Shiino, Eietsu Takahashi
-
Publication number: 20220065702Abstract: A semiconductor storage device includes a memory cell and a control circuit configured to, upon receipt of a command, acquire a first temperature measured by a temperature sensor, and perform an operation corresponding to the command using a parameter corrected based on temperature. When the first temperature is within a predetermined range with respect to a second temperature measured before the command is received, the parameter is corrected using the second temperature. When the first temperature is outside the predetermined range, the parameter is corrected using the first temperature.Type: ApplicationFiled: March 1, 2021Publication date: March 3, 2022Inventors: Keisuke TERADA, Eietsu TAKAHASHI
-
Publication number: 20210217481Abstract: A nonvolatile semiconductor memory device according to one embodiment of the present invention includes: a memory cell array and a control circuit. The control circuit executes a first reading operation and a second reading operation. The first reading operation is an operation of reading a threshold voltage set in the selected memory cell by setting a voltage between a control gate electrode and source of the selected memory cell to a first value. The second reading operation is an operation of reading a threshold voltage set in the selected memory cell by setting a voltage between the control gate electrode and source of the selected memory cell to a second value lower than the first value. When executing the second reading operation, the control circuit keeps a voltage of the control gate electrode of the selected memory cell to 0 or a positive value.Type: ApplicationFiled: March 31, 2021Publication date: July 15, 2021Applicant: Toshiba Memory CorporationInventors: Yasuhiro SHIINO, Eietsu TAKAHASHI, Koki UENO
-
Patent number: 11004520Abstract: A nonvolatile semiconductor memory device according to one embodiment of the present invention includes: a memory cell array and a control circuit. The control circuit executes a first reading operation and a second reading operation. The first reading operation is an operation of reading a threshold voltage set in the selected memory cell by setting a voltage between a control gate electrode and source of the selected memory cell to a first value. The second reading operation is an operation of reading a threshold voltage set in the selected memory cell by setting a voltage between the control gate electrode and source of the selected memory cell to a second value lower than the first value. When executing the second reading operation, the control circuit keeps a voltage of the control gate electrode of the selected memory cell to 0 or a positive value.Type: GrantFiled: September 21, 2020Date of Patent: May 11, 2021Assignee: Toshiba Memory CorporationInventors: Yasuhiro Shiino, Eietsu Takahashi, Koki Ueno
-
Publication number: 20210020249Abstract: A nonvolatile semiconductor memory device includes a control circuit configured to control a soft program operation of setting nonvolatile memory cells to a first threshold voltage distribution state of the nonvolatile memory cells. When a characteristic of the nonvolatile memory cells is in a first state, the control circuit executes the soft program operation by applying a first voltage for setting the nonvolatile memory cells to the first threshold voltage distribution state to first word lines, and applying a second voltage higher than the first voltage to a second word line. When the characteristic of the nonvolatile memory cells is in a second state, the control circuit executes the soft program operation by applying a third voltage equal to or lower than the first voltage to the first word lines and applying a fourth voltage lower than the second voltage to the second word line.Type: ApplicationFiled: October 6, 2020Publication date: January 21, 2021Applicant: TOSHIBA MEMORY CORPORATIONInventors: Yasuhiro SHIINO, Eietsu TAKAHASHI
-
Publication number: 20210005270Abstract: A nonvolatile semiconductor memory device according to one embodiment of the present invention includes: a memory cell array and a control circuit. The control circuit executes a first reading operation and a second reading operation. The first reading operation is an operation of reading a threshold voltage set in the selected memory cell by setting a voltage between a control gate electrode and source of the selected memory cell to a first value. The second reading operation is an operation of reading a threshold voltage set in the selected memory cell by setting a voltage between the control gate electrode and source of the selected memory cell to a second value lower than the first value. When executing the second reading operation, the control circuit keeps a voltage of the control gate electrode of the selected memory cell to 0 or a positive value.Type: ApplicationFiled: September 21, 2020Publication date: January 7, 2021Applicant: Toshiba Memory CorporationInventors: Yasuhiro SHIINO, Eietsu TAKAHASHI, Koki UENO
-
Patent number: 10839908Abstract: According to one embodiment, a semiconductor memory device includes: a memory string including first and second select transistors and memory cell transistors; a bit line connected to the first select transistor; word lines which are connected to gates of the memory cell transistors, respectively; first and second select gate lines which are connected to gates of the first and second select transistors, respectively; a first contact plug connected to the first select gate line; a first wiring layer provided on the first contact plug; a second contact plug connected to the second select gate line; a second wiring layer provided on the second contact plug; and a row decoder connected to the first and second wiring layers. The row decoder applies different voltages to the first select gate line and the second select gate line.Type: GrantFiled: November 22, 2019Date of Patent: November 17, 2020Assignee: Toshiba Memory CorporationInventors: Takashi Kobayashi, Yoichi Minemura, Eietsu Takahashi, Masaki Kondo, Daisuke Hagishima
-
Patent number: 10832777Abstract: A nonvolatile semiconductor memory device includes a control circuit configured to control a soft program operation of setting nonvolatile memory cells to a first threshold voltage distribution state of the nonvolatile memory cells. When a characteristic of the nonvolatile memory cells is in a first state, the control circuit executes the soft program operation by applying a first voltage for setting the nonvolatile memory cells to the first threshold voltage distribution state to first word lines, and applying a second voltage higher than the first voltage to a second word line. When the characteristic of the nonvolatile memory cells is in a second state, the control circuit executes the soft program operation by applying a third voltage equal to or lower than the first voltage to the first word lines and applying a fourth voltage lower than the second voltage to the second word line.Type: GrantFiled: September 18, 2019Date of Patent: November 10, 2020Assignee: TOSHIBA MEMORY CORPORATIONInventors: Yasuhiro Shiino, Eietsu Takahashi
-
Patent number: 10818362Abstract: A nonvolatile semiconductor memory device according to one embodiment of the present invention includes: a memory cell array and a control circuit. The control circuit executes a first reading operation and a second reading operation. The first reading operation is an operation of reading a threshold voltage set in the selected memory cell by setting a voltage between a control gate electrode and source of the selected memory cell to a first value. The second reading operation is an operation of reading a threshold voltage set in the selected memory cell by setting a voltage between the control gate electrode and source of the selected memory cell to a second value lower than the first value. When executing the second reading operation, the control circuit keeps a voltage of the control gate electrode of the selected memory cell to 0 or a positive value.Type: GrantFiled: October 9, 2019Date of Patent: October 27, 2020Assignee: Toshiba Memory CorporationInventors: Yasuhiro Shiino, Eietsu Takahashi, Koki Ueno