Patents by Inventor Koji Yamakawa

Koji Yamakawa 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: 20160099406
    Abstract: According to one embodiment, a magnetoresistive element includes a first magnetic layer having a perpendicular and invariable magnetization, a first nonmagnetic insulating layer on the first magnetic layer, a second magnetic layer on the first nonmagnetic insulating layer, the second magnetic layer having a perpendicular and variable magnetization, a second nonmagnetic insulating layer on the second magnetic layer, and a nonmagnetic conductive layer on the second nonmagnetic insulating layer. The second nonmagnetic insulating layer includes a first metal oxide with a predetermined element. The first nonmagnetic insulating layer includes a second metal oxide.
    Type: Application
    Filed: March 10, 2015
    Publication date: April 7, 2016
    Applicant: KABUSHIKI KAISHA TOSHIBA
    Inventors: Katsuya NISHIYAMA, Koji YAMAKAWA
  • Patent number: 9231192
    Abstract: According to one embodiment, a memory device with magnetroresistive effect element is disclosed. The element includes first metal magnetic film (MMF) with nonmagnetic element and axis of easy magnetization perpendicular (EMP), first insulating film, first intermediate magnetic film between the first MMF and the first insulating film, second MMF on the first insulating film and including nonmagnetic elements, the second MMF having axis of EMP, second intermediate magnetic film between the first insulating film and the second MMF, and diffusion preventing film including metal nitride having barrier property against diffusion of the nonmagnetic elements between the first MMF and the first intermediate magnetic film.
    Type: Grant
    Filed: January 6, 2014
    Date of Patent: January 5, 2016
    Assignee: Kabushiki Kaisha Toshiba
    Inventors: Daisuke Ikeno, Koji Yamakawa, Katsuaki Natori, Yasuyuki Sonoda
  • Patent number: 9196823
    Abstract: A magnetoresistive effect element includes the following structure. A first ferromagnetic layer has a variable magnetization direction. A second ferromagnetic layer has an invariable magnetization direction. A tunnel barrier layer is formed between the first and second ferromagnetic layers. An energy barrier between the first ferromagnetic layer and the tunnel barrier layer is higher than an energy barrier between the second ferromagnetic layer and the tunnel barrier layer. The second ferromagnetic layer contains a main component and an additive element. The main component contains at least one of Fe, Co, and Ni. The additive element contains at least one of Mg, Al, Ca, Sc, Ti, V, Mn, Zn, As, Sr, Y, Zr, Nb, Cd, In, Ba, La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu, Hf, Ta, and W.
    Type: Grant
    Filed: September 5, 2013
    Date of Patent: November 24, 2015
    Assignee: KABUSHIKI KAISHA TOSHIBA
    Inventors: Makoto Nagamine, Daisuke Ikeno, Koji Ueda, Katsuya Nishiyama, Katsuaki Natori, Koji Yamakawa
  • Patent number: 9196335
    Abstract: According to one embodiment, a magnetic memory includes magnetoresistive effect elements each including a first magnetic layer, a tunnel barrier layer, and a second magnetic layer which are successively stacked, and a ferroelectric capacitor provided above the magnetoresistive effect elements via an insulating layer, and including a lower electrode, a ferroelectric film, and an upper electrode which are successively stacked.
    Type: Grant
    Filed: August 8, 2013
    Date of Patent: November 24, 2015
    Assignee: KABUSHIKI KAISHA TOSHIBA
    Inventors: Katsuaki Natori, Koji Yamakawa
  • Patent number: 9070866
    Abstract: According to one embodiment, a magnetoresistive effect element includes a first ferromagnetic layer, a tunnel barrier formed on the first ferromagnetic layer, and a second ferromagnetic layer formed on the tunnel barrier layer. The tunnel barrier includes a nonmagnetic oxide having a spinel structure. Oxides forming the spinel structure are combined such that a single phase is formed by a solid phase in a component ratio region including a component ratio corresponding to the spinel structure and having a width of not less than 2%.
    Type: Grant
    Filed: August 7, 2013
    Date of Patent: June 30, 2015
    Assignee: KABUSHIKI KAISHA TOSHIBA
    Inventors: Makoto Nagamine, Daisuke Ikeno, Katsuya Nishiyama, Katsuaki Natori, Koji Yamakawa
  • Patent number: 8982614
    Abstract: According to one embodiment, a magnetoresistive effect element includes a first ferromagnetic layer, a tunnel barrier provided on the first ferromagnetic layer, and a second ferromagnetic layer provided on the tunnel barrier. The tunnel barrier includes a nonmagnetic mixture containing MgO and a metal oxide with a composition which forms, in a solid phase, a single phase with MgO.
    Type: Grant
    Filed: August 8, 2013
    Date of Patent: March 17, 2015
    Assignee: Kabushiki Kaisha Toshiba
    Inventors: Makoto Nagamine, Daisuke Ikeno, Katsuya Nishiyama, Katsuaki Natori, Koji Yamakawa
  • Publication number: 20150069556
    Abstract: According to one embodiment, a magnetic memory is disclosed. The magnetic memory includes a substrate, a first magnetoresistive element provided on the substrate. A second magnetoresistive element which is provided on the substrate and is arranged next to the first magnetoresistive element. Each of the first and second magnetoresistive elements includes a first magnetic layer, a tunnel barrier layer and a second magnetic layer. The tunnel barrier layer is provided on the first magnetic layer, the second magnetic layer is provided on the tunnel barrier layer. A first stress member having a tensile stress as an internal stress is provided on an area including a side face of the stacked body.
    Type: Application
    Filed: March 10, 2014
    Publication date: March 12, 2015
    Inventors: Koji YAMAKAWA, Sachiyo ITO, Masahiko HASUNUMA, Kenji NOMA, Hiroyuki YANO
  • Patent number: 8878320
    Abstract: According to one embodiment, a semiconductor memory device includes plural magneto-resistance elements being two-dimensionally arrayed on a semiconductor substrate. In the semiconductor memory device, each of the magneto-resistance elements includes: a first magnetic layer formed on the semiconductor substrate; a non-magnetic layer formed on the first magnetic layer; and a second magnetic layer formed on the non-magnetic layer, and an insulating film buried between the magneto-resistance elements adjacent to each other, a powder made of a metallic material or a magnetic material being dispersed in the insulating film.
    Type: Grant
    Filed: March 20, 2012
    Date of Patent: November 4, 2014
    Assignee: Kabushiki Kaisha Toshiba
    Inventors: Koji Yamakawa, Daisuke Ikeno, Yasuki Sonoda
  • Publication number: 20140284732
    Abstract: According to one embodiment, a magnetoresistive effect element includes a first ferromagnetic layer, a tunnel barrier formed on the first ferromagnetic layer, and a second ferromagnetic layer formed on the tunnel barrier layer. The tunnel barrier includes a nonmagnetic oxide having a spinel structure. Oxides forming the spinel structure are combined such that a single phase is formed by a solid phase in a component ratio region including a component ratio corresponding to the spinel structure and having a width of not less than 2%.
    Type: Application
    Filed: August 7, 2013
    Publication date: September 25, 2014
    Inventors: Makoto NAGAMINE, Daisuke IKENO, Katsuya NISHIYAMA, Katsuaki NATORI, Koji YAMAKAWA
  • Publication number: 20140284592
    Abstract: According to one embodiment, a magnetoresistive effect element includes a first ferromagnetic layer, a tunnel barrier provided on the first ferromagnetic layer, and a second ferromagnetic layer provided on the tunnel barrier. The tunnel barrier includes a nonmagnetic mixture containing MgO and a metal oxide with a composition which forms, in a solid phase, a single phase with MgO.
    Type: Application
    Filed: August 8, 2013
    Publication date: September 25, 2014
    Inventors: Makoto NAGAMINE, Daisuke IKENO, Katsuya NISHIYAMA, Katsuaki NATORI, Koji YAMAKAWA
  • Publication number: 20140269033
    Abstract: According to one embodiment, a magnetic memory includes magnetoresistive effect elements each including a first magnetic layer, a tunnel barrier layer, and a second magnetic layer which are successively stacked, and a ferroelectric capacitor provided above the magnetoresistive effect elements via an insulating layer, and including a lower electrode, a ferroelectric film, and an upper electrode which are successively stacked.
    Type: Application
    Filed: August 8, 2013
    Publication date: September 18, 2014
    Applicant: KABUSHIKI KAISHA TOSHIBA
    Inventors: Katsuaki NATORI, Koji YAMAKAWA
  • Patent number: 8741161
    Abstract: According to one embodiment, a method of manufacturing a semiconductor device, the method includes forming a pillar on a base layer, forming a insulating layer on the base layer to cover the pillar by using GCIB method, where a lowermost portion of an upper surface of the insulating layer is lower than an upper surface of the pillar, and polishing the insulating layer and the pillar to expose a head of the pillar by using CMP method, where an end point of the polishing is the lowermost portion of the upper surface of the insulating layer.
    Type: Grant
    Filed: March 23, 2012
    Date of Patent: June 3, 2014
    Assignee: Kabushiki Kaisha Toshiba
    Inventors: Yasuyuki Sonoda, Kyoichi Suguro, Masatoshi Yoshikawa, Koji Yamakawa, Katsuaki Natori, Daisuke Ikeno
  • Publication number: 20140117478
    Abstract: According to one embodiment, a memory device with magnetroresistive effect element is disclosed. The element includes first metal magnetic film (MMF) with nonmagnetic element and axis of easy magnetization perpendicular (EMP), first insulating film, first intermediate magnetic film between the first MMF and the first insulating film, second MMF on the first insulating film and including nonmagnetic elements, the second MMF having axis of EMP, second intermediate magnetic film between the first insulating film and the second MMF, and diffusion preventing film including metal nitride having barrier property against diffusion of the nonmagnetic elements between the first MMF and the first intermediate magnetic film.
    Type: Application
    Filed: January 6, 2014
    Publication date: May 1, 2014
    Applicant: KABUSHIKI KAISHA TOSHIBA
    Inventors: Daisuke Ikeno, Koji Yamakawa, Katsuaki Natori, Yasuyuki Sonoda
  • Patent number: 8710604
    Abstract: In accordance with an embodiment, a magnetoresistive element includes a lower electrode, a first magnetic layer on the lower electrode, a first diffusion prevention layer on the first magnetic layer, a first interfacial magnetic layer on the first metal layer, a nonmagnetic layer on the first interfacial magnetic layer, a second interfacial magnetic layer on the nonmagnetic layer, a second diffusion prevention layer on the second interfacial magnetic layer, a second magnetic layer on the second diffusion prevention layer, and an upper electrode layer on the second magnetic layer. The ratio of a crystal-oriented part to the other part in the second interfacial magnetic layer is higher than the ratio of a crystal-oriented part to the other part in the first interfacial magnetic layer.
    Type: Grant
    Filed: March 20, 2012
    Date of Patent: April 29, 2014
    Assignee: Kabushiki Kaisha Toshiba
    Inventors: Koji Yamakawa, Katsuaki Natori, Daisuke Ikeno, Tadashi Kai
  • Publication number: 20140085971
    Abstract: According to one embodiment, a magnetoresistive effect element includes the following structure. A first ferromagnetic layer has a variable magnetization direction. A second ferromagnetic layer has an invariable magnetization direction. A tunnel barrier layer is formed between the first and second ferromagnetic layers. An energy barrier between the first ferromagnetic layer and the tunnel barrier layer is higher than an energy barrier between the second ferromagnetic layer and the tunnel barrier layer. The second ferromagnetic layer contains a main component and an additive element. The main component contains at least one of Fe, Co, and Ni. The additive element contains at least one of Mg, Al, Ca, Sc, Ti, V, Mn, Zn, As, Sr, Y, Zr, Nb, Cd, In, Ba, La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu, Hf, Ta, and W.
    Type: Application
    Filed: September 5, 2013
    Publication date: March 27, 2014
    Inventors: Makoto NAGAMINE, Daisuke IKENO, Koji UEDA, Katsuya NISHIYAMA, Katsuaki NATORI, Koji YAMAKAWA
  • Publication number: 20140070289
    Abstract: According to one embodiment, a ferroelectric memory includes a gate insulation film formed on a semiconductor substrate, a ferroelectric film formed on the gate insulation film, and a control electrode formed on the ferroelectric film. The ferroelectric film is a film containing a metal, which is hafnium or zirconium, and oxygen, and contains an element other than the metal at a concentration lower than a concentration of the metal.
    Type: Application
    Filed: September 3, 2013
    Publication date: March 13, 2014
    Inventors: Masayuki TANAKA, Junichi WADA, Yoshio OZAWA, Koji YAMAKAWA, Seiji INUMIYA, Atsuko SAKATA
  • Publication number: 20140070290
    Abstract: According to one embodiment, a ferroelectric memory includes a semiconductor layer, an interfacial insulating film formed on the semiconductor layer, a ferroelectric film formed on the interfacial insulating film, and a gate electrode formed on the ferroelectric film, wherein the ferroelectric film is a film which includes a metal that is hafnium (Hf) or zirconium (Zr) and oxygen as the main components and to which an element selected from the group consisting of silicon (Si), magnesium (Mg), aluminum (Al).
    Type: Application
    Filed: September 6, 2013
    Publication date: March 13, 2014
    Applicant: KABUSHIKI KAISHA TOSHIBA
    Inventors: Seiji INUMIYA, Yoshio Ozawa, Koji Yamakawa, Atsuko Sakata, Masayuki Tanaka, Junichi Wada
  • Patent number: 8653614
    Abstract: According to one embodiment, a memory device with magnetroresistive effect element is disclosed. The element includes first metal magnetic film (MMF) with nonmagnetic element and axis of easy magnetization perpendicular (EMP), first insulating film, first intermediate magnetic film between the first MMF and the first insulating film, second MMF on the first insulating film and including nonmagnetic elements, the second MMF having axis of EMP, second intermediate magnetic film between the first insulating film and the second MMF, and diffusion preventing film including metal nitride having barrier property against diffusion of the nonmagnetic elements between the first MMF and the first intermediate magnetic film.
    Type: Grant
    Filed: February 28, 2012
    Date of Patent: February 18, 2014
    Assignee: Kabushiki Kaisha Toshiba
    Inventors: Daisuke Ikeno, Koji Yamakawa, Katsuaki Natori, Yasuyuki Sonoda
  • Publication number: 20140042568
    Abstract: A nonvolatile semiconductor memory device is provided with an MRAM chip including a magnetoresistive effect element having a reference layer whose magnetizing direction is set, a memory layer whose magnetizing direction is variable, and a nonmagnetic layer between these layers, and an enclosure having a thermal insulation area that covers part or the whole of the MRAM chip and prevents thermal fluctuation of the magnetization of the reference layer or memory layer.
    Type: Application
    Filed: March 7, 2013
    Publication date: February 13, 2014
    Applicant: Kabushiki Kaisha Toshiba
    Inventor: Koji YAMAKAWA
  • Patent number: 8638034
    Abstract: The multi-micro hollow cathode light source has a cathode plate, an insulation plate, an anode plate, and metal pieces. The insulation plate is sandwiched by the cathode plate and the anode plate. The cathode plate is made of copper. The centers of the cathode plate, insulation plate, and anode plate, are provided with holes, respectively. The holes form a penetrating though-hole. Linear slots are disposed in the cathode plate continuously extending from the hole in a cross shape. Each slot penetrates the cathode plate. Four metal pieces made of materials different from one another are inserted and buried in the four slots.
    Type: Grant
    Filed: February 8, 2011
    Date of Patent: January 28, 2014
    Assignees: National University Corporation Nagoya University, Meijo University, Nu Eco Engineering Co., Ltd., Katagiri Engineering Co., Ltd.
    Inventors: Masaru Hori, Masafumi Ito, Takayuki Ohta, Hiroyuki Kano, Koji Yamakawa