Patents by Inventor Tadashi Kai

Tadashi Kai 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: 9640752
    Abstract: According to one embodiment, a magnetoresistive element includes a recording layer having magnetic anisotropy perpendicular to a film surface and having a variable magnetization direction, a reference layer having magnetic anisotropy perpendicular to a film surface and having an invariable magnetization direction, an intermediate layer provided between the recording layer and the reference layer, and a underlayer containing AlTiN and provided on an opposite side of a surface of the recording layer on which the intermediate layer is provided.
    Type: Grant
    Filed: September 21, 2015
    Date of Patent: May 2, 2017
    Assignee: Kabushiki Kaisha Toshiba
    Inventors: Eiji Kitagawa, Tadashi Kai, Hiroaki Yoda
  • Publication number: 20170069687
    Abstract: According to one embodiment, a magnetoresistive memory device includes a stacked layer structure includes a first magnetic layer, a second magnetic layer, and a nonmagnetic layer between the first magnetic layer and the second magnetic layer, and a third magnetic layer provided on the first magnetic layer, which is opposite the nonmagnetic layer. The third magnetic layer includes a first magnetic material portion and a second magnetic material portion provided between the stacked layer structure and the first magnetic material portion. The saturation magnetization of the second magnetic material portion is smaller than that of the first magnetic material portion.
    Type: Application
    Filed: March 9, 2016
    Publication date: March 9, 2017
    Applicant: KABUSHIKI KAISHA TOSHIBA
    Inventors: Masahiko NAKAYAMA, Yutaka HASHIMOTO, Yasuyuki SONODA, Tadashi KAI, Kenji NOMA
  • Patent number: 9590174
    Abstract: According to one embodiment, a manufacturing method of a magnetoresistive memory device includes forming a first magnetic layer on a substrate, forming a magnetoresistive effect element on the first magnetic layer, forming a mask on a part of the magnetoresistive effect element, selectively etching the magnetoresistive effect element using the mask, forming a sidewall insulating film on a sidewall of the magnetoresistive effect element exposed by the etching, selectively etching the first magnetic layer using the mask and the sidewall insulating film and forming a deposition layer containing a magnetic material on a sidewall of the first magnetic layer and the sidewall insulating film, and introducing ions into the deposition layer.
    Type: Grant
    Filed: February 23, 2015
    Date of Patent: March 7, 2017
    Assignee: KABUSHIKI KAISHA TOSHIBA
    Inventors: Masaru Toko, Kuniaki Sugiura, Yutaka Hashimoto, Katsuya Nishiyama, Tadashi Kai
  • Publication number: 20160315251
    Abstract: A magnetoresistive element including a first magnetic layer; a first nonmagnetic layer provided on the first magnetic layer, the first nonmagnetic layer formed of SrTiO3, SrFeO3, LaAlO3, NdCoO3, or BN; and a second magnetic layer provided on the first nonmagnetic layer, wherein the first nonmagnetic layer is lattice-matched to the first magnetic layer, and the second magnetic layer is lattice-matched to the first nonmagnetic layer.
    Type: Application
    Filed: June 30, 2016
    Publication date: October 27, 2016
    Applicant: KABUSHIKI KAISHA TOSHIBA
    Inventors: Toshihiko NAGASE, Tadashi KAI, Youngmin EEH, Koji UEDA, Daisuke WATANABE, Kazuya SAWADA, Hiroaki YODA
  • Patent number: 9406871
    Abstract: According to one embodiment, a magnetoresistive element is disclosed. The magnetoresistive element includes a reference layer, a tunnel barrier layer, a storage layer. The storage layer includes a first region and a second region provided outside the first region to surround the first region, the second region including element included in the first region and another element being different from the element. The magnetoresistive element further includes a cap layer including a third region and a fourth region provided outside the third region to surround the third region, the fourth region including an element included in the third region and the another element.
    Type: Grant
    Filed: July 23, 2015
    Date of Patent: August 2, 2016
    Assignees: KABUSHIKI KAISHA TOSHIBA, SK HYNIX INC.
    Inventors: Masahiko Nakayama, Masatoshi Yoshikawa, Tadashi Kai, Yutaka Hashimoto, Masaru Toko, Hiroaki Yoda, Jae Geun Oh, Keum Bum Lee, Choon Kun Ryu, Hyung Suk Lee, Sook Joo Kim
  • Patent number: 9385304
    Abstract: According to one embodiment, a magnetic memory is disclosed. The memory includes a conductive layer containing a first metal material, a stacked body above the conductive layer, and including a first magnetization film containing a second metal material, a second magnetization film, and a tunnel barrier layer between the first magnetization film and the second magnetization film, and an insulating layer on a side face of the stacked body, and containing an oxide of the first metal material. The first magnetization film and/or the second magnetization film includes a first region positioned in a central portion, and a second region positioned in an edge portion and containing As, P, Ge, Ga, Sb, In, N, Ar, He, F, Cl, Br, I, Si, B, C, O, Zr, Tb, S, Se, or Ti.
    Type: Grant
    Filed: March 10, 2014
    Date of Patent: July 5, 2016
    Assignees: KABUSHIKI KAISHA TOSHIBA, SK HYNIX INC.
    Inventors: Masahiko Nakayama, Tadashi Kai, Masaru Toko, Hiroaki Yoda, Hyung Suk Lee, Jae Geun Oh, Choon Kun Ryu, Min Suk Lee
  • Patent number: 9373776
    Abstract: According to one embodiment, a magnetoresistive element includes first and second magnetic layers and a first nonmagnetic layer. The first magnetic layer has an axis of easy magnetization perpendicular to a film plane, and a variable magnetization. The second magnetic layer has an axis of easy magnetization perpendicular to a film plane, and an invariable magnetization. The first nonmagnetic layer is provided between the first and second magnetic layers. The second magnetic layer includes third and fourth magnetic layers, and a second nonmagnetic layer formed between the third and fourth magnetic layers. The third magnetic layer is in contact with the first nonmagnetic layer and includes Co and at least one of Zr, Nb, Mo, Hf, Ta, and W.
    Type: Grant
    Filed: December 12, 2014
    Date of Patent: June 21, 2016
    Assignee: Kabushiki Kaisha Toshiba
    Inventors: Toshihiko Nagase, Eiji Kitagawa, Katsuya Nishiyama, Tadashi Kai, Koji Ueda, Daisuke Watanabe
  • Patent number: 9368717
    Abstract: According to one embodiment, a magnetoresistive element is disclosed. The magnetoresistive element includes a reference layer. The reference layer includes a first region, and a second region provided outside the first region to surround the same. The second region contains an element contained in the first region and another element being different from the element. The magnetoresistive element further includes a storage layer, and a tunnel barrier layer provided between the reference layer and the storage layer. The storage layer is free from the another element.
    Type: Grant
    Filed: March 7, 2014
    Date of Patent: June 14, 2016
    Assignee: KABUSHIKI KAISHA TOSHIBA
    Inventors: Masaru Toko, Masahiko Nakayama, Kuniaki Sugiura, Yutaka Hashimoto, Tadashi Kai, Akiyuki Murayama, Tatsuya Kishi
  • Publication number: 20160104834
    Abstract: According to one embodiment, a manufacturing method of a magnetoresistive memory device includes forming a first magnetic layer on a substrate, forming a magnetoresistive effect element on the first magnetic layer, forming a mask on a part of the magnetoresistive effect element, selectively etching the magnetoresistive effect element using the mask, forming a sidewall insulating film on a sidewall of the magnetoresistive effect element exposed by the etching, selectively etching the first magnetic layer using the mask and the sidewall insulating film and forming a deposition layer containing a magnetic material on a sidewall of the first magnetic layer and the sidewall insulating film, and introducing ions into the deposition layer.
    Type: Application
    Filed: February 23, 2015
    Publication date: April 14, 2016
    Inventors: Masaru TOKO, Kuniaki SUGIURA, Yutaka HASHIMOTO, Katsuya NISHIYAMA, Tadashi KAI
  • Patent number: 9312477
    Abstract: According to one embodiment, a semiconductor storage device is disclosed. The device includes first magnetic layer, second magnetic layer, first nonmagnetic layer between them. The first magnetic layer includes a structure in which first magnetic material film, second magnetic material film, and nonmagnetic material film between the first and second magnetic material films are stacked. The first magnetic material film is nearest to the first nonmagnetic layer in the first magnetic layer. The nonmagnetic material film includes at least one of Ta, Zr, Nb, Mo, Ru, Ti, V, Cr, W, Hf. The second magnetic material film includes stacked materials, including first magnetic material nearest to the first nonmagnetic layer among the stacked materials, and second magnetic material which is same magnetic material as the first magnetic material and has smaller thickness than the first magnetic material.
    Type: Grant
    Filed: December 17, 2014
    Date of Patent: April 12, 2016
    Assignee: Kabushiki Kaisha Toshiba
    Inventors: Daisuke Watanabe, Katsuya Nishiyama, Toshihiko Nagase, Koji Ueda, Tadashi Kai
  • Patent number: 9312475
    Abstract: According to one embodiment, a magnetoresistive element includes first and second magnetic layers, a first nonmagnetic layer, a conductive layer. The first and second magnetic layers have axes of easy magnetization perpendicular to a film plane. The first and second magnetic layers have variable and invariable magnetization directions, respectively. The first nonmagnetic layer is between the first and second magnetic layers. The conductive layer is on a surface of the first magnetic layer opposite to a surface on which the first nonmagnetic layer is formed. The first magnetic layer has a structure obtained by alternately laminating magnetic and nonmagnetic materials. The nonmagnetic material includes at least one of Ta, W, Nb, Mo, Zr, Hf. The magnetic material includes Co and Fe. One of the magnetic materials contacts the first nonmagnetic layer. One of the nonmagnetic materials contacts the conductive layer.
    Type: Grant
    Filed: January 3, 2014
    Date of Patent: April 12, 2016
    Assignee: Kabushiki Kaisha Toshiba
    Inventors: Toshihiko Nagase, Daisuke Watanabe, Koji Ueda, Katsuya Nishiyama, Eiji Kitagawa, Kenji Noma, Tadashi Kai
  • Patent number: 9269890
    Abstract: According to one embodiment, a magnetoresistance effect element includes a reference layer, a shift canceling layer, a storage layer provided between the reference layer and the shift canceling layer, a tunnel barrier layer provided between the reference layer and the storage layer, and a spacer layer provided between the shift canceling layer and the storage layer, wherein a pattern of the storage layer is provided inside a pattern of the shift canceling layer when the patterns of the storage layer and the shift canceling layer are viewed from a direction perpendicular to the patterns of the storage layer and the shift canceling layer.
    Type: Grant
    Filed: August 29, 2013
    Date of Patent: February 23, 2016
    Inventors: Masahiko Nakayama, Toshihiko Nagase, Tadashi Kai, Youngmin Eeh, Koji Ueda, Yutaka Hashimoto, Daisuke Watanabe, Kazuya Sawada
  • Publication number: 20160013398
    Abstract: According to one embodiment, a magnetoresistive element includes a recording layer having a variable magnetization direction, a reference layer having an invariable magnetization direction, an intermediate layer provided between the recording layer and the reference layer, and a first buffer layer provided on a surface of the recording layer, which is opposite to a surface of the recording layer where the intermediate layer is provided. The recording layer comprises a first magnetic layer which is provided in a side of the intermediate layer and contains CoFe as a main component, and a second magnetic layer which is provided in a side of the first buffer layer and contains CoFe as a main component, a concentration of Fe in the first magnetic layer being higher than a concentration of Fe in the second magnetic layer. The first buffer layer comprises a nitrogen compound.
    Type: Application
    Filed: September 18, 2015
    Publication date: January 14, 2016
    Inventors: Eiji Kitagawa, Tadaomi Daibou, Tadashi Kai, Toshihiko Nagase, Kenji Noma, Hiroaki Yoda
  • Publication number: 20160013400
    Abstract: According to one embodiment, a magnetoresistive element includes a recording layer having magnetic anisotropy perpendicular to a film surface and having a variable magnetization direction, a reference layer having magnetic anisotropy perpendicular to a film surface and having an invariable magnetization direction, an intermediate layer provided between the recording layer and the reference layer, and a underlayer containing AlTiN and provided on an opposite side of a surface of the recording layer on which the intermediate layer is provided.
    Type: Application
    Filed: September 21, 2015
    Publication date: January 14, 2016
    Inventors: Eiji Kitagawa, Tadashi Kai, Hiroaki Yoda
  • Patent number: 9236563
    Abstract: According to one embodiment, a magnetic memory device includes a magnetoresistance effect element having a structure in which a first magnetic layer, a nonmagnetic layer, a second magnetic layer, and a third magnetic layer are stacked, wherein the third magnetic layer comprises a first region and a plurality of second regions, and each of the second regions is surrounded by the first region, has conductivity, and has a greater magnetic property than the first region.
    Type: Grant
    Filed: March 7, 2014
    Date of Patent: January 12, 2016
    Inventors: Yutaka Hashimoto, Tadashi Kai, Masahiko Nakayama, Hiroaki Yoda, Toshihiko Nagase, Masatoshi Yoshikawa, Yasuyuki Sonoda
  • Patent number: 9231196
    Abstract: According to one embodiment, a magnetoresistive element is disclosed. The element includes a lower electrode, a stacked body provided on the lower electrode and including a first magnetic layer, a tunnel barrier layer and a second magnetic layer. The first magnetic layer is under the tunnel barrier layer, the second magnetic layer is on the tunnel barrier layer. The first magnetic layer includes a first region and a second region outside the first region to surround the first region. The second region includes an element in the first region and other element being different from the element.
    Type: Grant
    Filed: March 7, 2014
    Date of Patent: January 5, 2016
    Inventors: Kuniaki Sugiura, Tadashi Kai
  • Patent number: 9219227
    Abstract: A magnetoresistive element according to an embodiment includes: a base layer; a first magnetic layer formed on the base layer, and including a first magnetic film having an axis of easy magnetization in a direction perpendicular to a film plane, the first magnetic film including MnxGa100-x (45?x<64 atomic %); a first nonmagnetic layer formed on the first magnetic layer; and a second magnetic layer formed on the first nonmagnetic layer, and including a second magnetic film having an axis of easy magnetization in a direction perpendicular to a film plane, the second magnetic film including MnyGa100-y (45?y<64 atomic %). The first and second magnetic layers include different Mn composition rates from each other, a magnetization direction of the first magnetic layer is changeable by a current flowing between the first magnetic layer and the second magnetic layer via the first nonmagnetic layer.
    Type: Grant
    Filed: November 20, 2014
    Date of Patent: December 22, 2015
    Assignees: KABUSHIKI KAISHA TOSHIBA, WPI-AIMR, Tohoku University
    Inventors: Tadaomi Daibou, Junichi Ito, Tadashi Kai, Minoru Amano, Hiroaki Yoda, Terunobu Miyazaki, Shigemi Mizukami, Koji Ando, Kay Yakushiji, Shinji Yuasa, Hitoshi Kubota, Akio Fukushima, Taro Nagahama, Takahide Kubota
  • Publication number: 20150325785
    Abstract: According to one embodiment, a magnetoresistive element is disclosed. The magnetoresistive element includes a reference layer, a tunnel barrier layer, a storage layer. The storage layer includes a first region and a second region provided outside the first region to surround the first region, the second region including element included in the first region and another element being different from the element. The magnetoresistive element further includes a cap layer including a third region and a fourth region provided outside the third region to surround the third region, the fourth region including an element included in the third region and the another element.
    Type: Application
    Filed: July 23, 2015
    Publication date: November 12, 2015
    Inventors: Masahiko NAKAYAMA, Masatoshi YOSHIKAWA, Tadashi KAI, Yutaka HASHIMOTO, Masaru TOKO, Hiroaki YODA, Jae Geun OH, Keum Bum LEE, Choon Kun RYU, Hyung Suk LEE, Sook Joo KIM
  • Patent number: 9184374
    Abstract: According to one embodiment, a magnetoresistive element includes first, second and third magnetic layers, and first and second nonmagnetic layers. The third magnetic layer has stack layers including a first stack layer close to the second magnetic layer, and a second stack layer far from the second magnetic layer. Each of the first and second stack layers includes a first layer made of a ferromagnetic material and a second layer made of a nonmagnetic material, and a first ratio of a film thickness of the first layer to that of the second layer in the first stack layer is higher than a second ratio of a film thickness of the first layer to that of the second layer in the second stack layer.
    Type: Grant
    Filed: August 9, 2013
    Date of Patent: November 10, 2015
    Inventors: Kazuya Sawada, Toshihiko Nagase, Youngmin Eeh, Koji Ueda, Daisuke Watanabe, Masahiko Nakayama, Tadashi Kai, Hiroaki Yoda
  • Patent number: 9178134
    Abstract: According to one embodiment, a magnetoresistive element is disclosed. The element includes a first magnetic film, a second magnetic film, and a first nonmagnetic layer formed between the first magnetic film and the second magnetic film. The second magnetic film includes a first magnetic layer formed on a side of the first nonmagnetic layer, a second magnetic layer formed on a side opposite to the first nonmagnetic layer, and a second nonmagnetic layer formed between the first magnetic layer and the second magnetic layer and containing TiN.
    Type: Grant
    Filed: March 10, 2014
    Date of Patent: November 3, 2015
    Inventors: Masahiko Nakayama, Tadashi Kai, Masaru Toko, Toshihiko Nagase, Hiroaki Yoda