Patents by Inventor Tadaaki Oikawa

Tadaaki Oikawa 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: 11201189
    Abstract: A semiconductor device includes a first rare earth oxide layer, a first magnetic layer adjacent to the first rare earth oxide layer, a second rare earth oxide layer, a second magnetic layer adjacent to the second rare earth oxide layer, and a nonmagnetic layer. The first magnetic layer is disposed between the first rare earth oxide layer and the nonmagnetic layer and is oriented in a crystal surface which is the same as a crystal surface of the nonmagnetic layer. The second magnetic layer is disposed between the second rare earth oxide layer and the nonmagnetic layer and is oriented in a crystal surface which is the same as a crystal surface of the nonmagnetic layer. The nonmagnetic layer is disposed between the first magnetic layer and the second magnetic layer.
    Type: Grant
    Filed: September 9, 2018
    Date of Patent: December 14, 2021
    Assignee: TOSHIBA MEMORY CORPORATION
    Inventors: Youngmin Eeh, Toshihiko Nagase, Daisuke Watanabe, Kazuya Sawada, Kenichi Yoshino, Tadaaki Oikawa, Hiroyuki Ohtori
  • Patent number: 11127445
    Abstract: According to one embodiment, a magnetic device includes a magnetic tunnel junction element, the magnetic tunnel junction element comprising: a first structure having ferromagnetism; a second structure having ferromagnetism; and a first nonmagnet provided between the first structure and the second structure; wherein: the first structure and the second structure are antiferromagnetically coupled via the first nonmagnet; and the first structure includes a first ferromagnetic nitride.
    Type: Grant
    Filed: March 13, 2019
    Date of Patent: September 21, 2021
    Assignees: TOSHIBA MEMORY CORPORATION, SK HYNIX INC.
    Inventors: Young Min Eeh, Taeyoung Lee, Kazuya Sawada, Eiji Kitagawa, Taiga Isoda, Tadaaki Oikawa, Kenichi Yoshino
  • Publication number: 20210288240
    Abstract: A magnetic memory device includes a magnetoresistance effect element including a first, second, and third ferromagnetic layer, a first non-magnetic layer between the first and second ferromagnetic layer, and a second non-magnetic layer between the second and third ferromagnetic layer. The second ferromagnetic layer is between the first and third ferromagnetic layer. The third ferromagnetic layer includes a fourth ferromagnetic layer in contact with the second non-magnetic layer, a third non-magnetic layer, and a fourth non-magnetic layer between the fourth ferromagnetic layer and the third non-magnetic layer. The first non-magnetic layer includes an oxide including magnesium (Mg). A melting point of the fourth non-magnetic layer is higher than the third non-magnetic layer.
    Type: Application
    Filed: September 9, 2020
    Publication date: September 16, 2021
    Applicant: Kioxia Corporation
    Inventors: Kazuya SAWADA, Young Min EEH, Tadaaki OIKAWA, Eiji KITAGAWA, Taiga ISODA
  • Publication number: 20210287728
    Abstract: According to one embodiment, a memory device includes: a first ferromagnetic layer; an insulating layer above the first ferromagnetic layer; a second ferromagnetic layer above the insulating layer; a capping layer on an upper surface of the second ferromagnetic layer; and an electrode on an upper surface of the capping layer. The second ferromagnetic layer includes iron atoms. The capping layer includes one or more elements identical to one or more elements in the second ferromagnetic layer. The electrode including one or more elements identical to one or more of the elements in the capping layer and includes a material having a Vickers hardness higher than a Vickers hardness of an iron atom.
    Type: Application
    Filed: September 9, 2020
    Publication date: September 16, 2021
    Applicants: Kioxia Corporation, SK hynix Inc.
    Inventors: Taiga ISODA, Eiji KITAGAWA, Young Min EEH, Tadaaki OIKAWA, Kazuya SAWADA, Jin Won JUNG
  • Publication number: 20210083170
    Abstract: According to one embodiment, a magnetic memory device includes a substrate, a first layer stack, and a second layer stack at a same side of the first layer stack relative to the substrate, and farther than the first layer stack from the substrate. Each of the first and second layer stack includes a reference layer, a tunnel barrier layer provided in a direction relative to the reference layer, the direction being perpendicular to the substrate, a storage layer provided in the direction relative to the tunnel barrier layer, and a first nonmagnetic layer provided in the direction relative to the storage layer. A heat absorption rate of the first nonmagnetic layer of the first layer stack is lower than a heat absorption rate of the first nonmagnetic layer of the second layer stack.
    Type: Application
    Filed: March 12, 2020
    Publication date: March 18, 2021
    Applicant: KIOXIA CORPORATION
    Inventors: Kazuya SAWADA, Young Min EEH, Eiji KITAGAWA, Taiga ISODA, Tadaaki OIKAWA, Kenichi YOSHINO
  • Publication number: 20210074908
    Abstract: According to one embodiment, a magnetic device includes a layer stack. The layer stack includes a first ferromagnetic layer, a second ferromagnetic layer, a first nonmagnetic layer between the first ferromagnetic layer and the second ferromagnetic layer, and a second nonmagnetic layer. The first ferromagnetic layer is interposed between the second nonmagnetic layer and the first nonmagnetic layer. The first nonmagnetic layer and the second nonmagnetic layer contain a magnesium oxide (MgO). The first ferromagnetic layer contains a higher amount of boron (B) at an interface with the first nonmagnetic layer than at an interface with the second nonmagnetic layer.
    Type: Application
    Filed: March 12, 2020
    Publication date: March 11, 2021
    Applicant: KIOXIA CORPORATION
    Inventors: Tadaaki OIKAWA, Young Min EEH, Kenichi YOSHINO, Eiji KITAGAWA, Kazuya SAWADA, Taiga ISODA
  • Publication number: 20210074911
    Abstract: According to one embodiment, a magnetoresistive memory device includes: a first ferromagnetic layer; a stoichiometric first layer; a first insulator between the first ferromagnetic layer and the first layer; a second ferromagnetic layer between the first insulator and the first layer; and a non-stoichiometric second layer between the second ferromagnetic layer and the first layer. The second layer is in contact with the second ferromagnetic layer and the first layer.
    Type: Application
    Filed: March 10, 2020
    Publication date: March 11, 2021
    Applicants: KIOXIA CORPORATION, SK HYNIX INC.
    Inventors: Taiga ISODA, Eiji KITAGAWA, Young Min EEH, Tadaaki OIKAWA, Kazuya SAWADA, Kenichi YOSHINO, Jong Koo LIM, Ku Youl JUNG, Guk Cheon KIM
  • Patent number: 10873021
    Abstract: According to one embodiment, a magnetic device includes a magnetoresistive effect element including a first ferromagnet, a conductor, and an oxide provided between the first ferromagnet and the conductor, the oxide including a first oxide of a rare-earth element and a second oxide of an element of which a covalent radius is smaller than a covalent radius of the rare-earth element.
    Type: Grant
    Filed: September 6, 2018
    Date of Patent: December 22, 2020
    Assignees: TOSHIBA MEMORY CORPORATION, SK HYNIX INC.
    Inventors: Young Min Eeh, Daisuke Watanabe, Jae-Hyoung Lee, Toshihiko Nagase, Kazuya Sawada, Tadaaki Oikawa, Kenichi Yoshino, Taiga Isoda
  • Patent number: 10840434
    Abstract: According to an embodiment, a storage device includes a resistance change element. The resistance change element includes a stacked structure including a first ferromagnet, a second ferromagnet, and a first nonmagnet between the first ferromagnet and the second ferromagnet. The first nonmagnet includes a boron-doped rare-earth oxide.
    Type: Grant
    Filed: March 13, 2019
    Date of Patent: November 17, 2020
    Assignee: TOSHIBA MEMORY CORPORATION
    Inventors: Eiji Kitagawa, Young Min Eeh, Tadaaki Oikawa, Kenichi Yoshino, Kazuya Sawada, Taiga Isoda
  • Publication number: 20200302987
    Abstract: According to one embodiment, a magnetic device includes: a first magnetic material provided above a substrate; a second magnetic material provided between the substrate and the first magnetic material; a nonmagnetic material provided between the first magnetic material and the second magnetic material; a first layer provided between the substrate and the second magnetic material and including an amorphous layer; and a second layer provided between the amorphous layer and the second magnetic material and including a crystal layer.
    Type: Application
    Filed: September 10, 2019
    Publication date: September 24, 2020
    Applicant: TOSHIBA MEMORY CORPORATION
    Inventors: Kazuya SAWADA, Young Min EEH, Tadaaki OIKAWA, Kenichi YOSHINO, Eiji KITAGAWA, Taiga ISODA
  • Publication number: 20200294567
    Abstract: According to one embodiment, a magnetoresistive element includes a first magnetic layer having an invariable magnetization direction; a non-magnetic layer provided on the first magnetic layer; a second magnetic layer provided on the non-magnetic layer, having an invariable magnetization direction, and containing a rare-earth element; a third magnetic layer provided on the second magnetic layer and composed of cobalt; and an oxide layer provided on the third magnetic layer.
    Type: Application
    Filed: September 11, 2019
    Publication date: September 17, 2020
    Applicant: TOSHIBA MEMORY CORPORATION
    Inventors: Tadaaki OIKAWA, Young Min EEH, Kazuya SAWADA, Kenichi YOSHINO, Eiji KITAGAWA, Taiga ISODA
  • Publication number: 20200091410
    Abstract: According to an embodiment, a storage device includes a resistance change element. The resistance change element includes a stacked structure including a first ferromagnet, a second ferromagnet, and a first nonmagnet between the first ferromagnet and the second ferromagnet. The first nonmagnet includes a boron-doped rare-earth oxide.
    Type: Application
    Filed: March 13, 2019
    Publication date: March 19, 2020
    Applicant: TOSHIBA MEMORY CORPORATION
    Inventors: Eiji KITAGAWA, Young Min EEH, Tadaaki OIKAWA, Kenichi YOSHINO, Kazuya SAWADA, Taiga ISODA
  • Publication number: 20200082857
    Abstract: According to one embodiment, a magnetic device includes a magnetic tunnel junction element, the magnetic tunnel junction element comprising: a first structure having ferromagnetism; a second structure having ferromagnetism; and a first nonmagnet provided between the first structure and the second structure; wherein: the first structure and the second structure are antiferromagnetically coupled via the first nonmagnet; and the first structure includes a first ferromagnetic nitride.
    Type: Application
    Filed: March 13, 2019
    Publication date: March 12, 2020
    Applicants: TOSHIBA MEMORY CORPORATION, SK HYNIX INC.
    Inventors: Young Min EEH, Taeyoung LEE, Kazuya SAWADA, Eiji KITAGAWA, Taiga ISODA, Tadaaki OIKAWA, Kenichi YOSHINO
  • Patent number: 10510950
    Abstract: A magnetoresistive memory device includes a first magnetic layer having a variable magnetization direction, a second magnetic layer, a magnetization direction of the second magnetic layer being invariable, a first nonmagnetic layer provided between the first magnetic layer and the second magnetic layer, and a second nonmagnetic layer provided on the first magnetic layer, which is opposite the first nonmagnetic layer. The first magnetic layer has a stacked layer structure in which an amorphous magnetic material layer is sandwiched between crystalline magnetic material layers. The magnetoresistive memory device further includes nonmagnetic material layers provided between one of the crystalline magnetic material layers and the amorphous magnetic material layer, and between the other crystalline magnetic layer and the amorphous magnetic material layer, respectively.
    Type: Grant
    Filed: July 5, 2019
    Date of Patent: December 17, 2019
    Assignee: TOSHIBA MEMORY CORPORATION
    Inventors: Daisuke Watanabe, Toshihiko Nagase, Youngmin Eeh, Kazuya Sawada, Makoto Nagamine, Tadaaki Oikawa, Kenichi Yoshino, Hiroyuki Ohtori
  • Patent number: 10490732
    Abstract: According to one embodiment, a magnetic memory device includes a stacked structure including a first magnetic layer, a second magnetic layer and a nonmagnetic layer between the first magnetic layer and the second magnetic layer, and a sidewall insulating layer provided on a side surface of the stacked structure and containing boron (B).
    Type: Grant
    Filed: September 16, 2016
    Date of Patent: November 26, 2019
    Assignee: TOSHIBA MEMORY CORPORATION
    Inventors: Yasuyuki Sonoda, Daisuke Watanabe, Masatoshi Yoshikawa, Youngmin Eeh, Shuichi Tsubata, Toshihiko Nagase, Yutaka Hashimoto, Kazuya Sawada, Kazuhiro Tomioka, Kenichi Yoshino, Tadaaki Oikawa
  • Patent number: 10468170
    Abstract: According to one embodiment, a magnetic device comprising a magnetoresistive effect element, wherein the magnetoresistive effect element includes: a first ferromagnetic body, a second ferromagnetic body, and a first rare-earth ferromagnetic oxide that is provided between the first ferromagnetic body and the second ferromagnetic body and magnetically joins the first ferromagnetic body and the second ferromagnetic body.
    Type: Grant
    Filed: March 13, 2018
    Date of Patent: November 5, 2019
    Assignee: TOSHIBA MEMORY CORPORATION
    Inventors: Young Min Eeh, Toshihiko Nagase, Daisuke Watanabe, Kazuya Sawada, Tadaaki Oikawa, Kenichi Yoshino
  • Publication number: 20190334081
    Abstract: A magnetoresistive memory device includes a first magnetic layer having a variable magnetization direction, a second magnetic layer, a magnetization direction of the second magnetic layer being invariable, a first nonmagnetic layer provided between the first magnetic layer and the second magnetic layer, and a second nonmagnetic layer provided on the first magnetic layer, which is opposite the first nonmagnetic layer. The first magnetic layer has a stacked layer structure in which an amorphous magnetic material layer is sandwiched between crystalline magnetic material layers. The magnetoresistive memory device further includes nonmagnetic material layers provided between one of the crystalline magnetic material layers and the amorphous magnetic material layer, and between the other crystalline magnetic layer and the amorphous magnetic material layer, respectively.
    Type: Application
    Filed: July 5, 2019
    Publication date: October 31, 2019
    Applicant: TOSHIBA MEMORY CORPORATION
    Inventors: Daisuke WATANABE, Toshihiko NAGASE, Youngmin EEH, Kazuya SAWADA, Makoto NAGAMINE, Tadaaki OIKAWA, Kenichi YOSHINO, Hiroyuki OHTORI
  • Publication number: 20190296226
    Abstract: According to one embodiment, a magnetic device includes a magnetoresistive effect element including a first ferromagnet, a conductor, and an oxide provided between the first ferromagnet and the conductor, the oxide including a first oxide of a rare-earth element and a second oxide of an element of which a covalent radius is smaller than a covalent radius of the rare-earth element.
    Type: Application
    Filed: September 6, 2018
    Publication date: September 26, 2019
    Applicants: TOSHIBA MEMORY CORPORATION, SK HYNIX INC.
    Inventors: Young Min EEH, Daisuke WATANABE, Jae-Hyoung LEE, Toshihiko NAGASE, Kazuya SAWADA, Tadaaki OIKAWA, Kenichi YOSHINO, Taiga ISODA
  • Patent number: 10388343
    Abstract: A magnetoresistive element includes: a first magnetic layer having a magnetization direction that is variable; a second magnetic layer having a magnetization direction that is invariable; a first non-magnetic layer provided between the first magnetic layer and the second magnetic layer; a third magnetic layer that fixes the magnetization direction of the second magnetic layer and that antiferromagnetically couples with the second magnetic layer; and a second non-magnetic layer provided between the second magnetic layer and the third magnetic layer. The second non-magnetic layer includes ruthenium (Ru) and a metal element.
    Type: Grant
    Filed: March 9, 2018
    Date of Patent: August 20, 2019
    Assignee: TOSHIBA MEMORY CORPORATION
    Inventors: Tadaaki Oikawa, Young Min Eeh, Kazuya Sawada, Kenichi Yoshino, Toshihiko Nagase, Daisuke Watanabe
  • Patent number: 10263178
    Abstract: According to one embodiment, a magnetic memory device includes a first magnetic layer having a variable magnetization direction, a second magnetic layer having a fixed magnetization direction, and a nonmagnetic layer between the first and second magnetic layers. The second magnetic layer includes a first main surface on the nonmagnetic layer side and a second main surface opposite to the first main surface, and includes a first region on the first main surface side and a second region on the second main surface side, and an intermediate region between the first and second regions and containing a predetermined nonmagnetic element. A concentration of the predetermined nonmagnetic element in the intermediate region is higher than that in the first and second regions. The second magnetic layer contains a magnetic element from the first to second main surfaces.
    Type: Grant
    Filed: March 20, 2017
    Date of Patent: April 16, 2019
    Assignee: TOSHIBA MEMORY CORPORATION
    Inventors: Kazuya Sawada, Toshihiko Nagase, Youngmin Eeh, Daisuke Watanabe, Kenichi Yoshino, Tadaaki Oikawa, Hiroyuki Ohtori