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).
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Patent number: 11990417Abstract: 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: GrantFiled: December 14, 2021Date of Patent: May 21, 2024Assignee: Kioxia CorporationInventors: Hiroki Kitayama, Mitsuo Ikeda, Daisuke Ikeno, Akihiro Kajita
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Publication number: 20240097044Abstract: 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: ApplicationFiled: August 25, 2023Publication date: March 21, 2024Inventors: Yusuke KASAHARA, Kappei IMAMURA, Akifumi GAWASE, Shinji MORI, Akihiro KAJITA
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Publication number: 20240081073Abstract: 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: ApplicationFiled: September 1, 2023Publication date: March 7, 2024Applicant: Kioxia CorporationInventors: Ryosuke UMINO, Daisuke IKENO, Masayuki KITAMURA, Akihiro KAJITA
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Publication number: 20230413555Abstract: 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: ApplicationFiled: March 2, 2023Publication date: December 21, 2023Inventors: Hiroki KITAYAMA, Tomotaka ARIGA, Mitsuo IKEDA, Daisuke IKENO, Akihiro KAJITA
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Publication number: 20230092843Abstract: 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: ApplicationFiled: February 25, 2022Publication date: March 23, 2023Inventors: Mitsuo IKEDA, Daisuke IKENO, Akihiro KAJITA
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Patent number: 11605643Abstract: 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: GrantFiled: March 10, 2021Date of Patent: March 14, 2023Assignee: Kioxia CorporationInventors: Daisuke Ikeno, Akihiro Kajita
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Publication number: 20230046783Abstract: 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: ApplicationFiled: December 14, 2021Publication date: February 16, 2023Applicant: Kioxia CorporationInventors: Hiroki KITAYAMA, Mitsuo IKEDA, Daisuke IKENO, Akihiro KAJITA
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Publication number: 20220406710Abstract: 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: ApplicationFiled: February 28, 2022Publication date: December 22, 2022Applicant: Kioxia CorporationInventors: Tatsuya NOMURA, Daichi NISHIKAWA, Daisuke IKENO, Akihiro KAJITA
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Patent number: 11527478Abstract: 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: GrantFiled: December 15, 2020Date of Patent: December 13, 2022Assignee: Kioxia CorporationInventors: Mitsuo Ikeda, Daisuke Ikeno, Akihiro Kajita
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Publication number: 20220085051Abstract: 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: ApplicationFiled: March 10, 2021Publication date: March 17, 2022Applicant: Kioxia CorporationInventors: Daisuke IKENO, Akihiro KAJITA
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Patent number: 11227934Abstract: 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: GrantFiled: March 2, 2020Date of Patent: January 18, 2022Assignee: KIOXIA CORPORATIONInventors: Mitsuo Ikeda, Daisuke Ikeno, Akihiro Kajita
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Publication number: 20210296238Abstract: 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: ApplicationFiled: December 15, 2020Publication date: September 23, 2021Applicant: Kioxia CorporationInventors: Mitsuo IKEDA, Daisuke IKENO, Akihiro KAJITA
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Patent number: 11114503Abstract: 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: GrantFiled: March 24, 2020Date of Patent: September 7, 2021Assignee: TOSHIBA MEMORY CORPORATIONInventors: Toshiya Murakami, Akihiro Kajita, Masumi Saitoh
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Publication number: 20210083069Abstract: 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: ApplicationFiled: March 2, 2020Publication date: March 18, 2021Applicant: KIOXIA CORPORATIONInventors: Mitsuo IKEDA, Daisuke IKENO, Akihiro KAJITA
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Patent number: 10833265Abstract: 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: GrantFiled: August 29, 2019Date of Patent: November 10, 2020Assignee: TOSHIBA MEMORY CORPORATIONInventors: Daisuke Ikeno, Akihiro Kajita, Atsuko Sakata
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Publication number: 20200303641Abstract: 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: ApplicationFiled: August 29, 2019Publication date: September 24, 2020Applicant: TOSHIBA MEMORY CORPORATIONInventors: Daisuke IKENO, Akihiro KAJITA, Atsuko SAKATA
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Patent number: 10741443Abstract: 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: GrantFiled: April 30, 2019Date of Patent: August 11, 2020Assignee: Kioxia CorporationInventors: Masayuki Kitamura, Atsuko Sakata, Makoto Wada, Yuichi Yamazaki, Masayuki Katagiri, Akihiro Kajita, Tadashi Sakai, Naoshi Sakuma, Ichiro Mizushima
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Publication number: 20200227479Abstract: 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: ApplicationFiled: March 24, 2020Publication date: July 16, 2020Applicant: TOSHIBA MEMORY CORPORATIONInventors: Toshiya MURAKAMI, Akihiro Kajita, Masumi Saitoh
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Patent number: 10644068Abstract: 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: GrantFiled: March 12, 2019Date of Patent: May 5, 2020Assignee: TOSHIBA MEMORY CORPORATIONInventors: Toshiya Murakami, Akihiro Kajita, Masumi Saitoh
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Publication number: 20200027923Abstract: 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: ApplicationFiled: March 12, 2019Publication date: January 23, 2020Applicant: TOSHIBA MEMORY CORPORATIONInventors: Toshiya MURAKAMI, Akihiro KAJITA, Masumi SAITOH