Patents by Inventor Kazuaki Isobe

Kazuaki Isobe 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: 11176999
    Abstract: According to one embodiment, a semiconductor memory device includes first to nth string units (n being a natural number of 3 or more), a plurality of layers of word lines, and (n?1) layers of select gate layers. The first to nth string units each includes a memory string. The memory string includes a plurality of memory cells and a plurality of select transistors connected in series in a first direction. The (n?1) layers of select gate layers include first to (2×(n?1))th select gates electrically isolated from each other. The first string unit is selected by the first to (n?1)th select gates. The kth string unit (k being not less than 1 and not more than n) is selected by the kth to (n+k?2)th select gates. The nth string unit is selected by the nth to (2×(n?1))th select gates.
    Type: Grant
    Filed: January 6, 2021
    Date of Patent: November 16, 2021
    Assignee: TOSHIBA MEMORY CORPORATION
    Inventors: Noboru Shibata, Kazuaki Isobe
  • Publication number: 20210125670
    Abstract: According to one embodiment, a semiconductor memory device includes first to nth string units (n being a natural number of 3 or more), a plurality of layers of word lines, and (n?1) layers of select gate layers. The first to nth string units each includes a memory string. The memory string includes a plurality of memory cells and a plurality of select transistors connected in series in a first direction. The (n?1) layers of select gate layers include first to (2×(n?1))th select gates electrically isolated from each other. The first string unit is selected by the first to (n?1)th select gates. The kth string unit (k being not less than 1 and not more than n) is selected by the kth to (n+k?2)th select gates. The nth string unit is selected by the nth to (2×(n?1))th select gates.
    Type: Application
    Filed: January 6, 2021
    Publication date: April 29, 2021
    Applicant: TOSHIBA MEMORY CORPORATION
    Inventors: Noboru SHIBATA, Kazuaki ISOBE
  • Patent number: 10902919
    Abstract: According to one embodiment, a semiconductor memory device includes first to nth string units (n being a natural number of 3 or more), a plurality of layers of word lines, and (n?1) layers of select gate layers. The first to nth string units each includes a memory string. The memory string includes a plurality of memory cells and a plurality of select transistors connected in series in a first direction. The (n?1) layers of select gate layers include first to (2×(n?1))th select gates electrically isolated from each other. The first string unit is selected by the first to (n?1)th select gates. The kth string unit (k being not less than 1 and not more than n) is selected by the kth to (n+k?2)th select gates. The nth string unit is selected by the nth to (2×(n?1))th select gates.
    Type: Grant
    Filed: May 15, 2020
    Date of Patent: January 26, 2021
    Assignee: TOSHIBA MEMORY CORPORATION
    Inventors: Noboru Shibata, Kazuaki Isobe
  • Publication number: 20200279608
    Abstract: According to one embodiment, a semiconductor memory device includes first to nth string units (n being a natural number of 3 or more), a plurality of layers of word lines, and (n?1) layers of select gate layers. The first to nth string units each includes a memory string. The memory string includes a plurality of memory cells and a plurality of select transistors connected in series in a first direction. The (n?1) layers of select gate layers include first to (2×(n?1))th select gates electrically isolated from each other. The first string unit is selected by the first to (n?1)th select gates. The kth string unit (k being not less than 1 and not more than n) is selected by the kth to (n+k?2)th select gates. The nth string unit is selected by the nth to (2×(n?1))th select gates.
    Type: Application
    Filed: May 15, 2020
    Publication date: September 3, 2020
    Applicant: Toshiba Memory Corporation
    Inventors: Noboru SHIBATA, Kazuaki ISOBE
  • Patent number: 10679700
    Abstract: According to one embodiment, a semiconductor memory device includes first to nth string units (n being a natural number of 3 or more), a plurality of layers of word lines, and (n?1) layers of select gate layers. The first to nth string units each includes a memory string. The memory string includes a plurality of memory cells and a plurality of select transistors connected in series in a first direction. The (n?1) layers of select gate layers include first to (2×(n?1))th select gates electrically isolated from each other. The first string unit is selected by the first to (n?1)th select gates. The kth string unit (k being not less than 1 and not more than n) is selected by the kth to (n+k?2)th select gates. The nth string unit is selected by the nth to (2×(n?1))th select gates.
    Type: Grant
    Filed: July 30, 2018
    Date of Patent: June 9, 2020
    Assignee: TOSHIBA MEMORY CORPORATION
    Inventors: Noboru Shibata, Kazuaki Isobe
  • Publication number: 20190122734
    Abstract: According to one embodiment, a semiconductor memory device includes first to nth string units (n being a natural number of 3 or more), a plurality of layers of word lines, and (n?1) layers of select gate layers. The first to nth string units each includes a memory string. The memory string includes a plurality of memory cells and a plurality of select transistors connected in series in a first direction. The (n?1) layers of select gate layers include first to (2×(n?1))th select gates electrically isolated from each other. The first string unit is selected by the first to (n?1)th select gates. The kth string unit (k being not less than 1 and not more than n) is selected by the kth to (n+k?2)th select gates. The nth string unit is selected by the nth to (2×(n?1))th select gates.
    Type: Application
    Filed: July 30, 2018
    Publication date: April 25, 2019
    Applicant: TOSHIBA MEMORY CORPORATION
    Inventors: Noboru Shibata, Kazuaki Isobe
  • Patent number: 8331156
    Abstract: According to one embodiment, a nonvolatile semiconductor storage device includes a first well region of a first conductivity type, a second well region of the first conductivity type, a third well region of a second conductivity type, a bit line and a column decoder. A first cell array including a plurality of memory cells is formed in the first well region. A second cell array including a plurality of memory cells is formed in the second well region. The third well region includes the first and second well regions. The bit line is connected to the memory cells included in the first cell array and the memory cells included in the second cell array. The column decoder is connected to the bit line.
    Type: Grant
    Filed: September 15, 2010
    Date of Patent: December 11, 2012
    Assignee: Kabushiki Kaisha Toshiba
    Inventors: Takamichi Kasai, Yoshiharu Hirata, Kazuaki Isobe, Akira Umezawa
  • Patent number: 8178412
    Abstract: A plurality of memory cells each constituted of a memory cell transistor having a gate electrode in a laminated structure composed of a charge storage layer and a control gate layer and a select transistor having source/drain diffusion layers while one of the source/drain diffusion layers is shared by the memory cell transistor are arranged in and on a semiconductor substrate. The impurity concentration of the source/drain diffusion layer shared by the memory cell transistor and the select transistor in each of the plurality of memory cells is set lower than the impurity concentration of the other source/drain diffusion layers in each of the memory cells.
    Type: Grant
    Filed: September 24, 2008
    Date of Patent: May 15, 2012
    Assignee: Kabushiki Kaisha Toshiba
    Inventor: Kazuaki Isobe
  • Patent number: 8012826
    Abstract: A semiconductor device in which a channel region of MOS transistor is provided not to include a non-flat active region end portion and a manufacturing method thereof is disclosed. According to one aspect, there is provided a semiconductor device comprising a semiconductor substrate, a device isolation separating active region, wherein at least a portion of the device isolation is provided in the semiconductor substrate, and a memory cell including a memory cell transistor that comprises a channel region separated by a slit and constituted of a flat active region alone, a charge storage layer provided on a gate dielectric on the channel region, and a first gate electrode provided on an inter-electrode dielectric so as to cover the charge storage layer, and a select transistor that comprises a second gate electrode provided on the gate dielectric on the active region and electrically connected to a wiring.
    Type: Grant
    Filed: November 19, 2009
    Date of Patent: September 6, 2011
    Assignee: Kabushiki Kaisha Toshiba
    Inventor: Kazuaki Isobe
  • Publication number: 20110205810
    Abstract: According to one embodiment, a nonvolatile semiconductor storage device includes a first well region of a first conductivity type, a second well region of the first conductivity type, a third well region of a second conductivity type, a bit line and a column decoder. A first cell array including a plurality of memory cells is formed in the first well region. A second cell array including a plurality of memory cells is formed in the second well region. The third well region includes the first and second well regions. The bit line is connected to the memory cells included in the first cell array and the memory cells included in the second cell array. The column decoder is connected to the bit line.
    Type: Application
    Filed: September 15, 2010
    Publication date: August 25, 2011
    Applicant: KABUSHIKI KAISHA TOSHIBA
    Inventors: Takamichi KASAI, Yoshiharu Hirata, Kazuaki Isobe, Akira Umezawa
  • Publication number: 20110031549
    Abstract: A memory includes active areas and an isolation on a semiconductor substrate. A tunnel dielectric film is on active areas. Floating gates include lower gate parts and upper gate parts. An upper gate part has a larger width than that of a lower gate part on a cross section perpendicular to an extension direction of an active area, and is provided on the lower gate part. An intermediate dielectric film is on an upper surface and a side surface of each floating gate. The control gate is on an upper surface and a side surface of each floating gate via the intermediate dielectric film. A height of a lower end of each control gate from a surface of the semiconductor substrate is lower than a height of an interface between the upper gate part and the lower gate part from the surface of the semiconductor substrate.
    Type: Application
    Filed: August 2, 2010
    Publication date: February 10, 2011
    Applicant: KABUSHIKI KAISHA TOSHIBA
    Inventors: Masaki Kondo, Kazuaki Isobe
  • Publication number: 20100068857
    Abstract: A semiconductor device in which a channel region of MOS transistor is provided not to include a non-flat active region end portion and a manufacturing method thereof is disclosed. According to one aspect, there is provided a semiconductor device comprising a semiconductor substrate, a device isolation separating active region, wherein at least a portion of the device isolation is provided in the semiconductor substrate, and a memory cell including a memory cell transistor that comprises a channel region separated by a slit and constituted of a flat active region alone, a charge storage layer provided on a gate dielectric on the channel region, and a first gate electrode provided on an inter-electrode dielectric so as to cover the charge storage layer, and a select transistor that comprises a second gate electrode provided on the gate dielectric on the active region and electrically connected to a wiring.
    Type: Application
    Filed: November 19, 2009
    Publication date: March 18, 2010
    Inventor: Kazuaki ISOBE
  • Patent number: 7633113
    Abstract: A semiconductor device in which a channel region of MOS transistor is provided not to include a non-flat active region end portion and a manufacturing method thereof is disclosed. According to one aspect, there is provided a semiconductor device comprising a semiconductor substrate, a device isolation separating active region, wherein at least a portion of the device isolation is provided in the semiconductor substrate, and a memory cell including a memory cell transistor that comprises a channel region separated by a slit and constituted of a flat active region alone, a charge storage layer provided on a gate dielectric on the channel region, and a first gate electrode provided on an inter-electrode dielectric so as to cover the charge storage layer, and a select transistor that comprises a second gate electrode provided on the gate dielectric on the active region and electrically connected to a wiring.
    Type: Grant
    Filed: April 23, 2007
    Date of Patent: December 15, 2009
    Assignee: Kabushiki Kaisha Toshiba
    Inventor: Kazuaki Isobe
  • Patent number: 7582927
    Abstract: A semiconductor device including a memory cell having a memory transistor and select gate transistor and a peripheral transistor is disclosed. The memory transistor has a stacked gate structure formed by sequentially stacking a gate insulating film, first gate electrode, inter-poly insulating film, and second gate electrode on a semiconductor substrate. The select gate transistor has a stacked gate structure identical to the memory transistor, and selects the memory transistor. The peripheral transistor forms a peripheral circuit of the memory cell, and has a gate electrode having a single-layer structure. A through hole reaching the first gate electrode is formed in the second gate electrode and inter-poly insulating film positioned on an element isolation film of the select gate transistor. A contact plug buried in this through hole electrically connects the second gate electrode and first gate electrode.
    Type: Grant
    Filed: October 26, 2006
    Date of Patent: September 1, 2009
    Assignee: Kabushiki Kaisha Toshiba
    Inventors: Kazuaki Isobe, Kanji Osari
  • Publication number: 20090090963
    Abstract: A plurality of memory cells each constituted of a memory cell transistor having a gate electrode in a laminated structure composed of a charge storage layer and a control gate layer and a select transistor having source/drain diffusion layers while one of the source/drain diffusion layers is shared by the memory cell transistor are arranged in and on a semiconductor substrate. The impurity concentration of the source/drain diffusion layer shared by the memory cell transistor and the select transistor in each of the plurality of memory cells is set lower than the impurity concentration of the other source/drain diffusion layers in each of the memory cells.
    Type: Application
    Filed: September 24, 2008
    Publication date: April 9, 2009
    Inventor: Kazuaki ISOBE
  • Publication number: 20070252188
    Abstract: A semiconductor device in which a channel region of MOS transistor is provided not to include a non-flat active region end portion and a manufacturing method thereof is disclosed. According to one aspect, there is provided a semiconductor device comprising a semiconductor substrate, a device isolation separating active region, wherein at least a portion of the device isolation is provided in the semiconductor substrate, and a memory cell including a memory cell transistor that comprises a channel region separated by a slit and constituted of a flat active region alone, a charge storage layer provided on a gate dielectric on the channel region, and a first gate electrode provided on an inter-electrode dielectric so as to cover the charge storage layer, and a select transistor that comprises a second gate electrode provided on the gate dielectric on the active region and electrically connected to a wiring.
    Type: Application
    Filed: April 23, 2007
    Publication date: November 1, 2007
    Inventor: Kazuaki Isobe
  • Publication number: 20070097746
    Abstract: A semiconductor device including a memory cell having a memory transistor and select gate transistor and a peripheral transistor is disclosed. The memory transistor has a stacked gate structure formed by sequentially stacking a gate insulating film, first gate electrode, inter-poly insulating film, and second gate electrode on a semiconductor substrate. The select gate transistor has a stacked gate structure identical to the memory transistor, and selects the memory transistor. The peripheral transistor forms a peripheral circuit of the memory cell, and has a gate electrode having a single-layer structure. A through hole reaching the first gate electrode is formed in the second gate electrode and inter-poly insulating film positioned on an element isolation film of the select gate transistor. A contact plug buried in this through hole electrically connects the second gate electrode and first gate electrode.
    Type: Application
    Filed: October 26, 2006
    Publication date: May 3, 2007
    Inventors: Kazuaki ISOBE, Kanji Osari
  • Patent number: 6900086
    Abstract: A first side-wall film is formed on the sides of a gate electrode of a high-voltage transistor, and a second side-wall film is provided on the first side-wall film. The first side-wall film has an etching rate lower that of a pre-metal dielectric, and the second side-wall film has an etching rate substantially equal to that of the of the pre-metal dielectric. The LDD of the high-voltage transistor is provided in that part of the semiconductor substrate which lies right below the first and second side-wall films. The source/drain diffusion layer of the high-voltage transistor is formed in that part of the substrate which is outside the second side-wall film. A first side-wall film having an etching rate lower than that of the pre-metal dielectric and/or a second side-wall film having an etching rate substantially equal to that of the pre-metal dielectric are provided on the sides of the gate electrode of the low voltage transistor.
    Type: Grant
    Filed: May 12, 2003
    Date of Patent: May 31, 2005
    Assignee: Kabushiki Kaisha Toshiba
    Inventors: Seiichi Mori, Toshiharu Watanabe, Masataka Takebuchi, Kazuaki Isobe
  • Publication number: 20050082628
    Abstract: A semiconductor device which is here disclosed includes a first wiring layer having a first lower end and a first upper end protruded more than the first lower end, and a second wiring layer having a second lower end and a second upper end protruded more than the second lower end, the second upper end facing the first upper end with the interposition of a first gap, and the second lower end facing the first lower end with the interposition of a second gap larger than the first gap.
    Type: Application
    Filed: December 19, 2003
    Publication date: April 21, 2005
    Inventors: Hirohisa Kawasaki, Kazuaki Isobe
  • Publication number: 20030203605
    Abstract: A first side-wall film is formed on the sides of a gate electrode of a high-voltage transistor, and a second side-wall film is provided on the first side-wall film. The first side-wall film has an etching rate lower that of a pre-metal dielectric, and the second side-wall film has an etching rate substantially equal to that of the of the pre-metal dielectric. The LDD of the high-voltage transistor is provided in that part of the semiconductor substrate which lies right below the first and second side-wall films. The source/drain diffusion layer of the high-voltage transistor is formed in that part of the substrate which is outside the second side-wall film. A first side-wall film having an etching rate lower than that of the pre-metal dielectric and/or a second side-wall film having an etching rate substantially equal to that of the pre-metal dielectric are provided on the sides of the gate electrode of the low voltage transistor.
    Type: Application
    Filed: May 12, 2003
    Publication date: October 30, 2003
    Applicant: Kabushiki Kaisha Toshiba
    Inventors: Seiichi Mori, Toshiharu Watanabe, Masataka Takebuchi, Kazuaki Isobe