Patents by Inventor Tatsuya Kishi

Tatsuya Kishi 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: 7265950
    Abstract: A magnetoresistance effect element includes a first ferromagnetic layer (1), insulating layer (3) overlying the first ferromagnetic layer, and second ferromagnetic layer (2) overlying the insulating layer. The insulating layer has formed a through hole (A) having an opening width not larger than 20 nm, and the first and second ferromagnetic layers are connected to each other via the through hole.
    Type: Grant
    Filed: September 8, 2004
    Date of Patent: September 4, 2007
    Assignee: Kabushiki Kaisha Toshiba
    Inventors: Shiho Okuno, Yuichi Ohsawa, Shigeru Haneda, Yuzo Kamiguchi, Tatsuya Kishi
  • Patent number: 7247506
    Abstract: There is provided a magnetic memory device which has a small switching current for a writing line and which has a small variation therein. A method for producing such a magnetic memory device includes: forming a magnetoresistive effect element; forming a first insulating film so as to cover the magnetoresistive effect element; forming a coating film so as to cover the first insulating film; exposing a top face of the magnetoresistive effect element; forming an upper writing line on the magnetoresistive effect element; exposing the first insulating film on a side portion of the magnetoresistive effect element by removing a part or all of the coating film; and forming a yoke structural member so as to cover at least a side portion of the upper writing line and so as to contact the exposed first insulating film on the side portion of the magnetoresistive effect element.
    Type: Grant
    Filed: March 27, 2006
    Date of Patent: July 24, 2007
    Assignee: Kabushiki Kaisha Toshiba
    Inventors: Minoru Amano, Tatsuya Kishi, Yoshiaki Saito, Tomomasa Ueda, Hiroaki Yoda
  • Patent number: 7245524
    Abstract: A magnetic memory device includes a first write wiring which runs in a first direction, a second write wiring which runs in a second direction different from the first direction, and a magnetoresistive element which is arranged at an intersection between the first and second write wirings, has a fixed layer, a recording layer, and a magnetoresistive layer sandwiched between the fixed layer and the recording layer, and has an axis of easy magnetization obliquely with respect to the first and second directions, the recording layer including a first ferromagnetic layer, a second ferromagnetic layer, and a first nonmagnetic layer sandwiched between the first and second ferromagnetic layers, in which first magnetization of the first ferromagnetic layer and second magnetization of the second ferromagnetic layer are ferromagnetically coupled, and a ferro-coupling constant C of a ferromagnetic coupling is 0.0001 erg/cm2?C?0.2 erg/cm2.
    Type: Grant
    Filed: October 21, 2005
    Date of Patent: July 17, 2007
    Assignee: Kabushiki Kaisha Toshiba
    Inventors: Hiroaki Yoda, Tadashi Kai, Masahiko Nakayama, Sumio Ikegawa, Tatsuya Kishi
  • Patent number: 7245464
    Abstract: A magnetoresistive effect element of a tunnel junction type includes a magnetic multi-layered film (1), ferromagnetic film (3) and intervening insulating film (2) such that a current flows between the magnetic multi-layered film and the ferromagnetic film, tunneling through the insulating film. The magnetic multi-layered film includes a first ferromagnetic layer, second ferromagnetic layer and anti-ferromagnetic layer inserted between the first and second ferromagnetic layers.
    Type: Grant
    Filed: March 3, 2005
    Date of Patent: July 17, 2007
    Assignee: Kabushiki Kaisha Toshiba
    Inventors: Tatsuya Kishi, Yoshiaki Saito, Minoru Amano, Shigeki Takahashi, Katsuya Nishiyama
  • Publication number: 20070159875
    Abstract: It is made possible to prevent the recording layer in the TMR element from assuming the intermediate state as perfectly as possible even if writing into the MRAM is conducted, as heretofore described. A write control method for a magnetoresistive random access memory including: applying a pulsative first magnetic field substantially parallel to the axis of easy magnetization of the recording layer and a pulsative second magnetic field substantially parallel to the axis of hard magnetization to the recording layer so as to cause a period of the pulsative first magnetic field and a period of the pulsative second magnetic field to overlap each other; and applying a pulsative third magnetic field having substantially the same direction as the pulsative first magnetic field to the recording layer at least once after applying the pulsative first magnetic field to the recording layer.
    Type: Application
    Filed: September 20, 2006
    Publication date: July 12, 2007
    Applicant: KABUSHIKI KAISHA TOSHIBA
    Inventors: Naoharu Shimomura, Tatsuya Kishi, Ryousuke Takizawa
  • Patent number: 7240419
    Abstract: A method of manufacturing a magnetoresistance effect element includes forming an insulating layer on a first ferromagnetic layer, forming an aperture reaching the first ferromagnetic layer by thrusting a needle from the top surface of the insulating layer, and depositing a ferromagnetic material to form a second ferromagnetic layer overlying the insulating layer which buries the aperture. The aperture can have an opening width not larger than 20 nm. A current flowing between the first ferromagnetic layer and the needle can be monitored, and thrusting of the needle can be interrupted when the current reaches a predetermined value.
    Type: Grant
    Filed: March 10, 2004
    Date of Patent: July 10, 2007
    Assignee: Kabushiki Kaisha Toshiba
    Inventors: Shiho Okuno, Yuichi Ohsawa, Shigeru Haneda, Yuzo Kamiguchi, Tatsuya Kishi
  • Publication number: 20070096229
    Abstract: A magnetoresistive element includes a magnetic recording layer which records information as a magnetization direction changes upon supplying a bidirectional current in an out-of-plane direction, a magnetic reference layer which has a fixed magnetization direction, and a nonmagnetic layer which is provided between the magnetic recording layer and the magnetic reference layer. The magnetic recording layer includes an interface magnetic layer which is provided in contact with the nonmagnetic layer and has a first magnetic anisotropy energy, and a magnetic stabilizing layer which has a second magnetic anisotropy energy higher than the first magnetic anisotropy energy.
    Type: Application
    Filed: October 23, 2006
    Publication date: May 3, 2007
    Inventors: Masatoshi Yoshikawa, Toshihiko Nagase, Eiji Kitagawa, Hiroaki Yoda, Tatsuya Kishi, Masahiko Nakayama
  • Publication number: 20070086121
    Abstract: A magnetoresistive element which records information by supplying spin-polarized electrons to a magnetic material, includes a first pinned layer which is made of a magnetic material and has a first magnetization directed in a direction perpendicular to a film surface, a free layer which is made of a magnetic material and has a second magnetization directed in the direction perpendicular to the film surface, the direction of the second magnetization reversing by the spin-polarized electrons, and a first nonmagnetic layer which is provided between the first pinned layer and the free layer. A saturation magnetization Ms of the free layer satisfies a relationship 0?Ms<?{square root over ( )}{Jw/(6nAt)}. Jw is a write current density, t is a thickness of the free layer, A is a constant.
    Type: Application
    Filed: September 22, 2006
    Publication date: April 19, 2007
    Inventors: Toshihiko Nagase, Masatoshi Yoshikawa, Eiji Kitagawa, Masahiko Nakayama, Tadashi Kai, Tatsuya Kishi, Hiroaki Yoda
  • Patent number: 7200034
    Abstract: A magnetic memory device includes a magnetoresistance effect element, and a first write interconnection which is arranged under the magnetoresistance effect element and has a first interconnection layer and a first yoke layer, the first interconnection layer having a portion projecting toward the magnetoresistance effect element, and the first yoke layer including a first, a second, and third regions. And the device includes a second write interconnection which is arranged above the magnetoresistance effect element and has a second interconnection layer and a second yoke layer, the second interconnection layer having a portion projecting toward the magnetoresistance effect element, and the second yoke layer including a fourth, a fifth, and sixth regions.
    Type: Grant
    Filed: February 18, 2005
    Date of Patent: April 3, 2007
    Assignee: Kabushiki Kaisha Toshiba
    Inventors: Takeshi Kajiyama, Tomomasa Ueda, Tatsuya Kishi, Hiroaki Yoda, Hisanori Aikawa, Masatoshi Yoshikawa
  • Patent number: 7190613
    Abstract: An MTJ element has two magnetic layers and a nonmagnetic layer. The resistance of the MTJ element, which varies depending on whether the two magnetic layers are magnetized parallel or antiparallel. In an MRAM adapted to write data into the MTJ element by causing a write wiring to generate induced magnetic flux and consequently changing the direction of magnetization of the recording layer, the MTJ element is a perpendicular MTJ element in which each of the two magnetic layers is magnetized in a direction perpendicular to its plane. The write wiring is placed in a direction perpendicular to the direction of the thickness of the MTJ element and applies a generated magnetic field to the magnetic layers of the MTJ element in the direction in which they are magnetized. Magnetic yokes hold the MTJ element in the direction of its thickness.
    Type: Grant
    Filed: June 8, 2004
    Date of Patent: March 13, 2007
    Assignee: Kabushiki Kaisha Toshiba
    Inventors: Toshihiko Nagase, Hiroaki Yoda, Masatoshi Yoshikawa, Tadashi Kai, Tatsuya Kishi, Hisanori Aikawa, Tomomasa Ueda
  • Publication number: 20070012972
    Abstract: A magnetic memory device includes a magnetoresistive element and a first wiring layer. The magnetoresistive element includes a fixed layer, a recording layer, and a non-magnetic layer interposed therebetween. The first wiring layer extends in a first direction and generates a magnetic field for recording data in the magnetoresistive element. The recording layer includes a base portion extending in a second direction rotated from the first direction by an angle falling within a range of more than 0° to not more than 20°, and first and second projections projecting from the first and second sides of the base portion in a third direction perpendicular to the second direction. The third and fourth sides of the base portion are inclined with respect to the third direction in the same rotational direction as a rotational direction in which the second direction is rotated.
    Type: Application
    Filed: March 27, 2006
    Publication date: January 18, 2007
    Inventors: Masahiko Nakayama, Tadashi Kai, Sumio Ikegawa, Yoshiaki Fukuzumi, Tatsuya Kishi
  • Patent number: 7164599
    Abstract: A data read method of a magnetic random access memory including a first wiring which runs in a first direction, a plurality of second wirings which run in a second direction different from the first direction, and a plurality of magnetoresistive elements which are arranged at intersections of the first wiring and the second wirings between the first wiring and the second wirings and electrically connected to the first wiring, includes to read out data of a selected element selected from the plurality of magnetoresistive elements, reading a resistance value of the selected element by a second current supplied from the first wiring to the selected element while supplying a first current to a selected wiring selected from the second wirings in correspondence with the selected element.
    Type: Grant
    Filed: October 6, 2005
    Date of Patent: January 16, 2007
    Assignee: Kabushiki Kaisha Toshiba
    Inventors: Keiji Hosotani, Tatsuya Kishi
  • Patent number: 7140096
    Abstract: A method of manufacturing a magnetoresistance effect device, including: forming a first ferromagnetic body, a nonmagnetic dielectric layer on the first ferromagnetic body, and a second ferromagnetic body on the nonmagnetic dielectric layer; etching part of an external region of a predetermined ferromagnetic tunnel junction region using a first linear mask pattern which is traversing the predetermined ferromagnetic tunnel junction region; and etching another part of the external region of the predetermined ferromagnetic tunnel junction region using a second linear mask pattern which is traversing the predetermined ferromagnetic tunnel junction region and intersecting with the first linear mask pattern.
    Type: Grant
    Filed: July 25, 2003
    Date of Patent: November 28, 2006
    Assignee: Kabushiki Kaisha Toshiba
    Inventors: Tatsuya Kishi, Shigeki Takahashi, Kentaro Nakajima, Minoru Amano, Masayuki Sagoi, Yoshiaki Saito
  • Publication number: 20060233017
    Abstract: A data read method of a magnetic random access memory including a first wiring which runs in a first direction, a plurality of second wirings which run in a second direction different from the first direction, and a plurality of magnetoresistive elements which are arranged at intersections of the first wiring and the second wirings between the first wiring and the second wirings and electrically connected to the first wiring, includes to read out data of a selected element selected from the plurality of magnetoresistive elements, reading a resistance value of the selected element by a second current supplied from the first wiring to the selected element while supplying a first current to a selected wiring selected from the second wirings in correspondence with the selected element.
    Type: Application
    Filed: October 6, 2005
    Publication date: October 19, 2006
    Inventors: Keiji Hosotani, Tatsuya Kishi
  • Publication number: 20060198184
    Abstract: A magnetic memory device includes a first write wiring which runs in a first direction, a second write wiring which runs in a second direction different from the first direction, and a magnetoresistive element which is arranged at an intersection between the first and second write wirings, has a fixed layer, a recording layer, and a magnetoresistive layer sandwiched between the fixed layer and the recording layer, and has an axis of easy magnetization obliquely with respect to the first and second directions, the recording layer including a first ferromagnetic layer, a second ferromagnetic layer, and a first nonmagnetic layer sandwiched between the first and second ferromagnetic layers, in which first magnetization of the first ferromagnetic layer and second magnetization of the second ferromagnetic layer are ferromagnetically coupled, and a ferro-coupling constant C of a ferromagnetic coupling is 0.0001 erg/cm2?C?0.2 erg/cm2.
    Type: Application
    Filed: October 21, 2005
    Publication date: September 7, 2006
    Inventors: Hiroaki Yoda, Tadashi Kai, Masahiko Nakayama, Sumio Ikegawa, Tatsuya Kishi
  • Publication number: 20060163196
    Abstract: There is provided a magnetic memory device which has a small switching current for a writing line and which has a small variation therein. A method for producing such a magnetic memory device includes: forming a magnetoresistive effect element; forming a first insulating film so as to cover the magnetoresistive effect element; forming a coating film so as to cover the first insulating film; exposing a top face of the magnetoresistive effect element; forming an upper writing line on the magnetoresistive effect element; exposing the first insulating film on a side portion of the magnetoresistive effect element by removing a part or all of the coating film; and forming a yoke structural member so as to cover at least a side portion of the upper writing line and so as to contact the exposed first insulating film on the side portion of the magnetoresistive effect element.
    Type: Application
    Filed: March 27, 2006
    Publication date: July 27, 2006
    Applicant: Kabushiki Kaisha Toshiba
    Inventors: Minoru Amano, Tatsuya Kishi, Yoshiaki Saito, Tomomasa Ueda, Hiroaki Yoda
  • Publication number: 20060146451
    Abstract: A magnetoresistive element has a ferromagnetic double tunnel junction having a stacked structure of a first antiferromagnetic layer/a first ferromagnetic layer/a first dielectric layer/a second ferromagnetic layer/a second dielectric layer/a third ferromagnetic layer/a second antiferromagnetic layer. The second ferromagnetic layer that is a free layer consists of a Co-based alloy or a three-layered film of a Co-based alloy/a Ni—Fe alloy/a Co-based alloy. A tunnel current is flowed between the first ferromagnetic layer and the third ferromagnetic layer.
    Type: Application
    Filed: March 6, 2006
    Publication date: July 6, 2006
    Applicant: KABUSHI KAISHA TOSHIBA
    Inventors: Koichiro Inomata, Kentaro Nakajima, Yoshiaki Saito, Masayuki Sagoi, Tatsuya Kishi
  • Publication number: 20060146599
    Abstract: The magnetic memory includes a plurality of memory cells, each memory cell including: at least one writing wire; at least one data storage portion, provided on at least one portion of an outer periphery of the writing wire, which comprises a ferromagnetic material whose magnetization direction can be inverted by causing a current to flow in the writing wire; and at least one magneto-resistance effect element, disposed in the vicinity of the data storage portion, which senses the magnetization direction of the data storage portion.
    Type: Application
    Filed: March 7, 2006
    Publication date: July 6, 2006
    Applicant: KABUSHIKI KAISHA TOSHIBA
    Inventors: Minoru Amano, Tatsuya Kishi, Sumino Ikegawa, Yoshiaki Saito, Hiroaki Yoda
  • Publication number: 20060132984
    Abstract: A magnetic memory device includes a magnetoresistance effect element, and a first write interconnection which is arranged under the magnetoresistance effect element and has a first interconnection layer and a first yoke layer, the first interconnection layer having a portion projecting toward the magnetoresistance effect element, and the first yoke layer including a first, a second, and third regions. And the device includes a second write interconnection which is arranged above the magnetoresistance effect element and has a second interconnection layer and a second yoke layer, the second interconnection layer having a portion projecting toward the magnetoresistance effect element, and the second yoke layer including a fourth, a fifth, and sixth regions.
    Type: Application
    Filed: February 18, 2005
    Publication date: June 22, 2006
    Inventors: Takeshi Kajiyama, Tomomasa Ueda, Tatsuya Kishi, Hiroaki Yoda, Hisanori Aikawa, Masatoshi Yoshikawa
  • Patent number: 7064402
    Abstract: A magnetic random access memory concerning an example of the present invention comprises a magneto resistive element, a first insulating layer which covers side surfaces of the magneto resistive element, a second insulating layer which is arranged on the first insulating layer and has a first groove on the magneto resistive element, a write line which fills the first groove and is connected with the magneto resistive element, and a third insulating layer which is arranged between the first and second insulating layers except a bottom portion of the first groove and has an etching selection ratio with respect to at least the first and second insulating layers.
    Type: Grant
    Filed: July 27, 2005
    Date of Patent: June 20, 2006
    Assignee: Kabushiki Kaisha Toshiba
    Inventors: Takeshi Kajiyama, Tomomasa Ueda, Tatsuya Kishi, Hisanori Aikawa, Masatoshi Yoshikawa, Yoshiaki Asao, Hiroaki Yoda