Patents by Inventor Akihiro Kajita

Akihiro Kajita 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: 11990417
    Abstract: A semiconductor memory device includes a first insulating layer, a first conductive layer, a first pillar, a second pillar, and a second insulating layer. The first conductive layer contains tungsten. The first conductive layer includes a first sub conductive layer and a second sub conductive layer. The first pillar and the second pillar pass through the first insulating layer and the first conductive layer. The second insulating layer divides the first insulating layer and the first conductive layer. The first sub conductive layer is in contact with the second sub conductive layer and is provided between the second sub conductive layer and the first insulating layer. A fluorine concentration in the first sub conductive layer is lower than that in the second sub conductive layer.
    Type: Grant
    Filed: December 14, 2021
    Date of Patent: May 21, 2024
    Assignee: Kioxia Corporation
    Inventors: Hiroki Kitayama, Mitsuo Ikeda, Daisuke Ikeno, Akihiro Kajita
  • Publication number: 20240097044
    Abstract: According to one embodiment, a semiconductor device includes a first conductive layer between first and second insulating layers with an oxide semiconductor column extending in the first direction through these layers. A third insulating layer covers the column. The column has a first semiconductor portion at a first position matching the first insulating layer, a second semiconductor portion at a second position matching second insulating layer, and a third semiconductor portion at a third position matching the first conductive layer. The first semiconductor portion is continuous along a second direction between the third insulating layer, the second semiconductor portion is continuous along the second direction between the third insulating layer, but the third semiconductor portion is not continuous between the third insulating layer.
    Type: Application
    Filed: August 25, 2023
    Publication date: March 21, 2024
    Inventors: Yusuke KASAHARA, Kappei IMAMURA, Akifumi GAWASE, Shinji MORI, Akihiro KAJITA
  • Publication number: 20240081073
    Abstract: A semiconductor device according to the present disclosure includes a first insulating film, a second insulating film, and a tungsten film provided between the first insulating film and the second insulating film, the tungsten film having a crystal particle, wherein a thickness T of the tungsten film in a first direction from the first insulating film toward the second insulating film and an average particle size APS of the crystal particle satisfy APS/T?2 is satisfied.
    Type: Application
    Filed: September 1, 2023
    Publication date: March 7, 2024
    Applicant: Kioxia Corporation
    Inventors: Ryosuke UMINO, Daisuke IKENO, Masayuki KITAMURA, Akihiro KAJITA
  • Publication number: 20230413555
    Abstract: According to one embodiment, a semiconductor storage device includes a memory pillar extending in a first direction. The memory pillar includes a tunnel insulation film, a charge storage layer on the tunnel insulation film, and a first block insulation film on the charge storage layer. A conductor layer extends in a second direction intersecting the first direction to meet a portion of the memory pillar. The conductor layer includes a first layer comprising molybdenum and a second layer comprising tungsten. The first layer is between the memory pillar and the second layer in the second direction.
    Type: Application
    Filed: March 2, 2023
    Publication date: December 21, 2023
    Inventors: Hiroki KITAYAMA, Tomotaka ARIGA, Mitsuo IKEDA, Daisuke IKENO, Akihiro KAJITA
  • Publication number: 20230092843
    Abstract: According to one embodiment, a semiconductor device includes a tunnel insulating film, a charge trap film on the tunnel insulating film, and a block insulating film on the charge trap film. The charge trap film is between the tunnel insulating film and the block insulating film. A conductive film is on the block insulating film. The block insulating film is between the charge trap film and the conductive film. The conductive film includes a first metal film adjacent to the block insulating film and a second metal film on the first metal film. The first metal film is between the block insulating film and the second metal film. The first metal film has an interfacial roughness on a side facing the second metal film that is greater than an interfacial roughness on a side facing the block insulating film.
    Type: Application
    Filed: February 25, 2022
    Publication date: March 23, 2023
    Inventors: Mitsuo IKEDA, Daisuke IKENO, Akihiro KAJITA
  • Patent number: 11605643
    Abstract: A semiconductor memory device according to an embodiment includes a semiconductor substrate, a first insulating layer, a second insulating layer, the first insulating layer between the semiconductor substrate and the second insulating layer, a semiconductor layer between the first insulating layer and the second insulating layer, the semiconductor layer extending in a first direction parallel to a surface of the semiconductor substrate, a gate electrode layer extending in a direction perpendicular to the surface; a first insulating film between the semiconductor layer and the gate electrode layer, a second insulating film between the first insulating film and the gate electrode layer the second insulating film in contact with the first insulating layer and the second insulating layer, a polycrystalline silicon region between the first insulating film and the second insulating film; and a metal film between the polycrystalline silicon region and the second insulating film containing titanium and silicon.
    Type: Grant
    Filed: March 10, 2021
    Date of Patent: March 14, 2023
    Assignee: Kioxia Corporation
    Inventors: Daisuke Ikeno, Akihiro Kajita
  • Publication number: 20230046783
    Abstract: A semiconductor memory device includes a first insulating layer, a first conductive layer, a first pillar, a second pillar, and a second insulating layer. The first conductive layer contains tungsten. The first conductive layer includes a first sub conductive layer and a second sub conductive layer. The first pillar and the second pillar pass through the first insulating layer and the first conductive layer. The second insulating layer divides the first insulating layer and the first conductive layer. The first sub conductive layer is in contact with the second sub conductive layer and is provided between the second sub conductive layer and the first insulating layer. A fluorine concentration in the first sub conductive layer is lower than that in the second sub conductive layer.
    Type: Application
    Filed: December 14, 2021
    Publication date: February 16, 2023
    Applicant: Kioxia Corporation
    Inventors: Hiroki KITAYAMA, Mitsuo IKEDA, Daisuke IKENO, Akihiro KAJITA
  • Publication number: 20220406710
    Abstract: A semiconductor device includes a conductive layer extending in a first direction, including a first surface, a second surface facing the first surface in a second direction intersecting the first direction, a third surface, and a fourth surface facing the third surface in a third direction intersecting the first direction and the second direction, and containing a first element which is at least one element of tungsten (W) or molybdenum (Mo); a first region disposed on a first surface side of the conductive layer, containing a second element which is at least one element of tungsten (W) or molybdenum (Mo), and a third element which is at least one element of sulfur (S), selenium (Se), or tellurium (Te), and including a first crystal; and a second region disposed on a second surface side of the conductive layer, containing the second element and the third element, and including a second crystal.
    Type: Application
    Filed: February 28, 2022
    Publication date: December 22, 2022
    Applicant: Kioxia Corporation
    Inventors: Tatsuya NOMURA, Daichi NISHIKAWA, Daisuke IKENO, Akihiro KAJITA
  • Patent number: 11527478
    Abstract: A semiconductor device according to an embodiment includes: a semiconductor substrate; a conductor including tungsten (W) or molybdenum (Mo); a first film provided between the conductor and the semiconductor substrate and including titanium (Ti) and silicon (Si); an insulating layer surrounding the conductor; and a second film provided between the conductor and the insulating layer, surrounding the conductor, and including titanium (Ti) and nitrogen (N). A first distance between the semiconductor substrate and an end portion of the second film on a side opposite to the semiconductor substrate is smaller than a second distance between the semiconductor substrate and an end portion of the conductor on a side opposite to the semiconductor substrate.
    Type: Grant
    Filed: December 15, 2020
    Date of Patent: December 13, 2022
    Assignee: Kioxia Corporation
    Inventors: Mitsuo Ikeda, Daisuke Ikeno, Akihiro Kajita
  • Publication number: 20220085051
    Abstract: A semiconductor memory device according to an embodiment includes a semiconductor substrate, a first insulating layer, a second insulating layer, the first insulating layer between the semiconductor substrate and the second insulating layer, a semiconductor layer between the first insulating layer and the second insulating layer, the semiconductor layer extending in a first direction parallel to a surface of the semiconductor substrate, a gate electrode layer extending in a direction perpendicular to the surface; a first insulating film between the semiconductor layer and the gate electrode layer, a second insulating film between the first insulating film and the gate electrode layer the second insulating film in contact with the first insulating layer and the second insulating layer, a polycrystalline silicon region between the first insulating film and the second insulating film; and a metal film between the polycrystalline silicon region and the second insulating film containing titanium and silicon.
    Type: Application
    Filed: March 10, 2021
    Publication date: March 17, 2022
    Applicant: Kioxia Corporation
    Inventors: Daisuke IKENO, Akihiro KAJITA
  • Patent number: 11227934
    Abstract: According to one embodiment, a semiconductor device includes a substrate, a plurality of insulating films and a plurality of electrode films provided alternately on the substrate. The semiconductor device further includes a first insulating film, a first charge storage film, a third insulating film, a second charge storage film, a second insulating film, and a first semiconductor film that are sequentially provided along at least one side surface of each of the electrode films. The first charge storage film includes either (i) molybdenum, or (ii) titanium and nitrogen, and the second charge storage film includes a semiconductor film.
    Type: Grant
    Filed: March 2, 2020
    Date of Patent: January 18, 2022
    Assignee: KIOXIA CORPORATION
    Inventors: Mitsuo Ikeda, Daisuke Ikeno, Akihiro Kajita
  • Publication number: 20210296238
    Abstract: A semiconductor device according to an embodiment includes: a semiconductor substrate; a conductor including tungsten (W) or molybdenum (Mo); a first film provided between the conductor and the semiconductor substrate and including titanium (Ti) and silicon (Si); an insulating layer surrounding the conductor; and a second film provided between the conductor and the insulating layer, surrounding the conductor, and including titanium (Ti) and nitrogen (N). A first distance between the semiconductor substrate and an end portion of the second film on a side opposite to the semiconductor substrate is smaller than a second distance between the semiconductor substrate and an end portion of the conductor on a side opposite to the semiconductor substrate.
    Type: Application
    Filed: December 15, 2020
    Publication date: September 23, 2021
    Applicant: Kioxia Corporation
    Inventors: Mitsuo IKEDA, Daisuke IKENO, Akihiro KAJITA
  • Patent number: 11114503
    Abstract: According to one embodiment, a memory device includes first and second electrically conductive portions, a first variable resistance portion, and a first region. A direction from the first electrically conductive portion toward the second electrically conductive portion is aligned with a first direction. The first variable resistance portion is provided between the first and second electrically conductive portions. A second direction from the first variable resistance portion toward the first region crosses the first direction. The first region includes a first layer portion, and a second layer portion provided between the first layer portion and the first variable resistance portion in the second direction. A first distance between the first and second layer portions is longer than first or second lattice length. The first lattice length is a lattice length of the first layer portion. The second lattice length is a lattice length of the second layer portion.
    Type: Grant
    Filed: March 24, 2020
    Date of Patent: September 7, 2021
    Assignee: TOSHIBA MEMORY CORPORATION
    Inventors: Toshiya Murakami, Akihiro Kajita, Masumi Saitoh
  • Publication number: 20210083069
    Abstract: According to one embodiment, a semiconductor device includes a substrate, a plurality of insulating films and a plurality of electrode films provided alternately on the substrate. The semiconductor device further includes a first insulating film, a first charge storage film, a third insulating film, a second charge storage film, a second insulating film, and a first semiconductor film that are sequentially provided along at least one side surface of each of the electrode films. The first charge storage film includes either (i) molybdenum, or (ii) titanium and nitrogen, and the second charge storage film includes a semiconductor film.
    Type: Application
    Filed: March 2, 2020
    Publication date: March 18, 2021
    Applicant: KIOXIA CORPORATION
    Inventors: Mitsuo IKEDA, Daisuke IKENO, Akihiro KAJITA
  • Patent number: 10833265
    Abstract: According to one embodiment, a storage device includes a first conductive layer, a second conductive layer, a resistance-variable layer, between the first conductive layer and the second conductive layer, that includes germanium, antimony, and tellurium, a first layer, between the resistance-variable layer and the first conductive layer, that includes carbon, a second layer, between the resistance-variable layer and the second conductive layer, that includes carbon, a third layer, between the resistance-variable layer and the first layer, that includes at least one of tungsten nitride or tungsten carbide, and a fourth layer, between the resistance-variable layer and the second layer, that includes at least one of tungsten nitride or tungsten carbide.
    Type: Grant
    Filed: August 29, 2019
    Date of Patent: November 10, 2020
    Assignee: TOSHIBA MEMORY CORPORATION
    Inventors: Daisuke Ikeno, Akihiro Kajita, Atsuko Sakata
  • Publication number: 20200303641
    Abstract: According to one embodiment, a storage device includes a first conductive layer, a second conductive layer, a resistance-variable layer, between the first conductive layer and the second conductive layer, that includes germanium, antimony, and tellurium, a first layer, between the resistance-variable layer and the first conductive layer, that includes carbon, a second layer, between the resistance-variable layer and the second conductive layer, that includes carbon, a third layer, between the resistance-variable layer and the first layer, that includes at least one of tungsten nitride or tungsten carbide, and a fourth layer, between the resistance-variable layer and the second layer, that includes at least one of tungsten nitride or tungsten carbide.
    Type: Application
    Filed: August 29, 2019
    Publication date: September 24, 2020
    Applicant: TOSHIBA MEMORY CORPORATION
    Inventors: Daisuke IKENO, Akihiro KAJITA, Atsuko SAKATA
  • Patent number: 10741443
    Abstract: According to one embodiment, a method for manufacturing a semiconductor device is disclosed. The method includes forming a co-catalyst layer and catalyst layer above a surface of a semiconductor substrate. The co-catalyst layer and catalyst layer have fcc structure. The fcc structure is formed such that (111) face of the fcc structure is to be oriented parallel to the surface of the semiconductor substrate. The catalyst includes a portion which contacts the co-catalyst layer. The portion has the fcc structure. An exposed surface of the catalyst layer is planarized by oxidation and reduction treatments. A graphene layer is formed on the catalyst layer.
    Type: Grant
    Filed: April 30, 2019
    Date of Patent: August 11, 2020
    Assignee: Kioxia Corporation
    Inventors: Masayuki Kitamura, Atsuko Sakata, Makoto Wada, Yuichi Yamazaki, Masayuki Katagiri, Akihiro Kajita, Tadashi Sakai, Naoshi Sakuma, Ichiro Mizushima
  • Publication number: 20200227479
    Abstract: According to one embodiment, a memory device includes first and second electrically conductive portions, a first variable resistance portion, and a first region. A direction from the first electrically conductive portion toward the second electrically conductive portion is aligned with a first direction. The first variable resistance portion is provided between the first and second electrically conductive portions. A second direction from the first variable resistance portion toward the first region crosses the first direction. The first region includes a first layer portion, and a second layer portion provided between the first layer portion and the first variable resistance portion in the second direction. A first distance between the first and second layer portions is longer than first or second lattice length. The first lattice length is a lattice length of the first layer portion. The second lattice length is a lattice length of the second layer portion.
    Type: Application
    Filed: March 24, 2020
    Publication date: July 16, 2020
    Applicant: TOSHIBA MEMORY CORPORATION
    Inventors: Toshiya MURAKAMI, Akihiro Kajita, Masumi Saitoh
  • Patent number: 10644068
    Abstract: According to one embodiment, a memory device includes first and second electrically conductive portions, a first variable resistance portion, and a first region. A direction from the first electrically conductive portion toward the second electrically conductive portion is aligned with a first direction. The first variable resistance portion is provided between the first and second electrically conductive portions. A second direction from the first variable resistance portion toward the first region crosses the first direction. The first region includes a first layer portion, and a second layer portion provided between the first layer portion and the first variable resistance portion in the second direction. A first distance between the first and second layer portions is longer than first or second lattice length. The first lattice length is a lattice length of the first layer portion. The second lattice length is a lattice length of the second layer portion.
    Type: Grant
    Filed: March 12, 2019
    Date of Patent: May 5, 2020
    Assignee: TOSHIBA MEMORY CORPORATION
    Inventors: Toshiya Murakami, Akihiro Kajita, Masumi Saitoh
  • Publication number: 20200027923
    Abstract: According to one embodiment, a memory device includes first and second electrically conductive portions, a first variable resistance portion, and a first region. A direction from the first electrically conductive portion toward the second electrically conductive portion is aligned with a first direction. The first variable resistance portion is provided between the first and second electrically conductive portions. A second direction from the first variable resistance portion toward the first region crosses the first direction. The first region includes a first layer portion, and a second layer portion provided between the first layer portion and the first variable resistance portion in the second direction. A first distance between the first and second layer portions is longer than first or second lattice length. The first lattice length is a lattice length of the first layer portion. The second lattice length is a lattice length of the second layer portion.
    Type: Application
    Filed: March 12, 2019
    Publication date: January 23, 2020
    Applicant: TOSHIBA MEMORY CORPORATION
    Inventors: Toshiya MURAKAMI, Akihiro KAJITA, Masumi SAITOH