Patents by Inventor Natsuki Sakaguchi

Natsuki Sakaguchi 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: 20240096413
    Abstract: 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.
    Type: Application
    Filed: March 2, 2023
    Publication date: March 21, 2024
    Inventors: Natsuki SAKAGUCHI, Takashi MAEDA, Rieko FUNATSUKI, Hidehiro SHIGA
  • Patent number: 9007845
    Abstract: In performing a read operation of a memory transistor, a control circuit supplies a first voltage to a selected word line connected to a selected memory transistor. A second voltage is supplied to a non-selected word line connected to a non-selected memory transistor other than the selected memory transistor, the second voltage being higher than the first voltage. A third voltage is supplied to a bit line. A fourth voltage lower than the third voltage is supplied to, among source lines, a selected source line connected to a memory string including the selected memory transistor in a selected memory block. A fifth voltage substantially the same as the third voltage is supplied to, among the source lines, a non-selected source line connected to a non-selected memory string in the selected memory block.
    Type: Grant
    Filed: June 19, 2014
    Date of Patent: April 14, 2015
    Assignee: Kabushiki Kaisha Toshiba
    Inventors: Hiroshi Maejima, Natsuki Sakaguchi
  • Patent number: 8917557
    Abstract: According to one embodiment, a nonvolatile semiconductor memory device comprises a semiconductor substrate, memory strings formed above the semiconductor substrate, and a control circuit configured to control voltages applied to the memory cells. In a read operation, when the control circuit precharges a first source line electrically connected to a selected memory string to a first voltage, the control circuit precharges a second source line electrically connected to an unselected memory string to a second voltage, the second voltage being higher than the first voltage, and after the second source line is precharged, the control circuit precharges a first bit line electrically connected to the selected memory string to the second voltage.
    Type: Grant
    Filed: December 14, 2012
    Date of Patent: December 23, 2014
    Assignee: Kabushiki Kaisha Toshiba
    Inventors: Natsuki Sakaguchi, Hiroshi Maejima
  • Publication number: 20140301144
    Abstract: In performing a read operation of a memory transistor, a control circuit supplies a first voltage to a selected word line connected to a selected memory transistor. A second voltage is supplied to a non-selected word line connected to a non-selected memory transistor other than the selected memory transistor, the second voltage being higher than the first voltage. A third voltage is supplied to a bit line. A fourth voltage lower than the third voltage is supplied to, among source lines, a selected source line connected to a memory string including the selected memory transistor in a selected memory block. A fifth voltage substantially the same as the third voltage is supplied to, among the source lines, a non-selected source line connected to a non-selected memory string in the selected memory block.
    Type: Application
    Filed: June 19, 2014
    Publication date: October 9, 2014
    Applicant: KABUSHIKI KAISHA TOSHIBA
    Inventors: Hiroshi Maejima, Natsuki Sakaguchi
  • Publication number: 20140233320
    Abstract: A nonvolatile semiconductor memory device includes a memory cell, a bit line electrically connected to the memory cell, a sense amplifier that includes a first transistor having a first end electrically connected to the bit line, a second transistor electrically connected between a second end of the first transistor and ground, a third transistor electrically connected between a second end of the first transistor and a source line, and a controller configured to control the first, second, and third transistors after performing a program operation. After the program operation, the first and second transistors are turned on and then while the first transistor remains turned on, the second transistor is turned off and the third transistor is turned on.
    Type: Application
    Filed: August 29, 2013
    Publication date: August 21, 2014
    Applicant: KABUSHIKI KAISHA TOSHIBA
    Inventors: Natsuki SAKAGUCHI, Hiroshi MAEJIMA
  • Patent number: 8797801
    Abstract: In performing a read operation of a memory transistor, a control circuit supplies a first voltage to a selected word line connected to a selected memory transistor. A second voltage is supplied to a non-selected word line connected to a non-selected memory transistor other than the selected memory transistor, the second voltage being higher than the first voltage. A third voltage is supplied to a bit line. A fourth voltage lower than the third voltage is supplied to, among source lines, a selected source line connected to a memory string including the selected memory transistor in a selected memory block. A fifth voltage substantially the same as the third voltage is supplied to, among the source lines, a non-selected source line connected to a non-selected memory string in the selected memory block.
    Type: Grant
    Filed: August 20, 2013
    Date of Patent: August 5, 2014
    Assignee: Kabushiki Kaisha Toshiba
    Inventors: Hiroshi Maejima, Natsuki Sakaguchi
  • Publication number: 20130336062
    Abstract: In performing a read operation of a memory transistor, a control circuit supplies a first voltage to a selected word line connected to a selected memory transistor. A second voltage is supplied to a non-selected word line connected to a non-selected memory transistor other than the selected memory transistor, the second voltage being higher than the first voltage. A third voltage is supplied to a bit line. A fourth voltage lower than the third voltage is supplied to, among source lines, a selected source line connected to a memory string including the selected memory transistor in a selected memory block. A fifth voltage substantially the same as the third voltage is supplied to, among the source lines, a non-selected source line connected to a non-selected memory string in the selected memory block.
    Type: Application
    Filed: August 20, 2013
    Publication date: December 19, 2013
    Applicant: Kabushiki Kaisha Toshiba
    Inventors: Hiroshi Maejima, Natsuki Sakaguchi
  • Patent number: 8542533
    Abstract: In performing a read operation of a memory transistor, a control circuit supplies a first voltage to a selected word line connected to a selected memory transistor. A second voltage is supplied to a non-selected word line connected to a non-selected memory transistor other than the selected memory transistor, the second voltage being higher than the first voltage. A third voltage is supplied to a bit line. A fourth voltage lower than the third voltage is supplied to, among source lines, a selected source line connected to a memory string including the selected memory transistor in a selected memory block. A fifth voltage substantially the same as the third voltage is supplied to, among the source lines, a non-selected source line connected to a non-selected memory string in the selected memory block.
    Type: Grant
    Filed: March 20, 2012
    Date of Patent: September 24, 2013
    Assignee: Kabushiki Kaisha Toshiba
    Inventors: Hiroshi Maejima, Natsuki Sakaguchi
  • Publication number: 20130155778
    Abstract: According to one embodiment, a nonvolatile semiconductor memory device comprises a semiconductor substrate, memory strings formed above the semiconductor substrate, and a control circuit configured to control voltages applied to the memory cells. In a read operation, when the control circuit precharges a first source line electrically connected to a selected memory string to a first voltage, the control circuit precharges a second source line electrically connected to an unselected memory string to a second voltage, the second voltage being higher than the first voltage, and after the second source line is precharged, the control circuit precharges a first bit line electrically connected to the selected memory string to the second voltage.
    Type: Application
    Filed: December 14, 2012
    Publication date: June 20, 2013
    Inventors: Natsuki Sakaguchi, Hiroshi Maejima
  • Publication number: 20120320678
    Abstract: In performing a read operation of a memory transistor, a control circuit supplies a first voltage to a selected word line connected to a selected memory transistor. A second voltage is supplied to a non-selected word line connected to a non-selected memory transistor other than the selected memory transistor, the second voltage being higher than the first voltage. A third voltage is supplied to a bit line. A fourth voltage lower than the third voltage is supplied to, among source lines, a selected source line connected to a memory string including the selected memory transistor in a selected memory block. A fifth voltage substantially the same as the third voltage is supplied to, among the source lines, a non-selected source line connected to a non-selected memory string in the selected memory block.
    Type: Application
    Filed: March 20, 2012
    Publication date: December 20, 2012
    Applicant: Kabushiki Kaisha Toshiba
    Inventors: Hiroshi MAEJIMA, Natsuki Sakaguchi