Patents by Inventor Ken-ichi Shimura

Ken-ichi Shimura 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: 7742263
    Abstract: A magnetoresistance device is provided for improving thermal stability of a magnetoresistance element by preventing inter-diffusion between a conductor (such as a via and an interconnection) for connecting the magnetoresistance element to another element and layers constituting the magnetoresistance element. A magnetoresistance device is composed of a magnetoresistance element, a non-magnetic conductor providing electrical connection between the magnetoresistance element to another element, and a diffusion barrier structure disposed between the conductor and the magnetoresistance element, the magnetoresistance element including a free ferromagnetic layer having reversible spontaneous magnetization, a fixed ferromagnetic layer having fixed spontaneous magnetization, and a tunnel dielectric layer disposed between the free and fixed ferroelectric layers.
    Type: Grant
    Filed: June 12, 2008
    Date of Patent: June 22, 2010
    Assignee: NEC Corporation
    Inventors: Yoshiyuki Fukumoto, Ken-ichi Shimura, Atsushi Kamijo
  • Publication number: 20080278867
    Abstract: A magnetoresistance device is provided for improving thermal stability of a magnetoresistance element by preventing inter-diffusion between a conductor (such as a via and an interconnection) for connecting the magnetoresistance element to another element and layers constituting the magnetoresistance element. A magnetoresistance device is composed of a magnetoresistance element, a non-magnetic conductor providing electrical connection between said magnetoresistance element to another element, and a diffusion barrier structure disposed between said conductor and said magnetoresistance element, the magnetoresistance element including a free ferromagnetic layer having reversible spontaneous magnetization, a fixed ferromagnetic layer having fixed spontaneous magnetization, and a tunnel dielectric layer disposed between said free and fixed ferroelectric layer.
    Type: Application
    Filed: June 12, 2008
    Publication date: November 13, 2008
    Applicant: NEC CORPORATION
    Inventors: Yoshiyuki FUKUMOTO, Ken-ichi SHIMURA, Atsushi KAMIJO
  • Patent number: 7394626
    Abstract: A magnetoresistance device is provided for improving thermal stability of a magnetoresistance element by preventing inter-diffusion between a conductor (such as a via and an interconnection) for connecting the magnetoresistance element to another element and layers constituting the magnetoresistance element. A magnetoresistance device is composed of a magnetoresistance element, a non-magnetic conductor providing electrical connection between said magnetoresistance element to another element, and a diffusion barrier structure disposed between the conductor and said magnetoresistance element, the magnetoresistance element including a free ferromagnetic layer having reversible spontaneous magnetization, a fixed ferromagnetic layer having fixed spontaneous magnetization, and a tunnel dielectric layer disposed between said free and fixed ferroelectric layer.
    Type: Grant
    Filed: October 31, 2003
    Date of Patent: July 1, 2008
    Assignee: NEC Corporation
    Inventors: Yoshiyuki Fukumoto, Ken-ichi Shimura, Atsushi Kamijo
  • Patent number: 7379280
    Abstract: A magneto-resistance device is composed of an anti-ferromagnetic layer (5), a pinned ferromagnetic layer (20), a tunnel insulating layer (9) and a free ferromagnetic layer (21). The pinned ferromagnetic layer (20) is connected to the anti-ferromagnetic layer (5) and has a fixed spontaneous magnetization. The tunnel insulating layer (9) is connected to the pinned ferromagnetic layer (20) and is non-magnetic. The free ferromagnetic layer (21) is connected to the tunnel insulating layer (9) and has a reversible free spontaneous magnetization. The pinned ferromagnetic layer (20) has a first composite magnetic layer (6) to prevent at lest one component of the anti-ferromagnetic layer (5) from diffusing into tunnel insulating layer (9).
    Type: Grant
    Filed: December 16, 2003
    Date of Patent: May 27, 2008
    Assignee: NEC Corporation
    Inventors: Yoshiyuki Fukumoto, Ken-ichi Shimura, Atsushi Kamijo
  • Patent number: 7187525
    Abstract: The heat resistance of a magnetic resistance device utilizing the TMR effect is improved. Also, the Neel effect of the magnetic resistance device utilizing the TMR effect is restrained. The magnetic resistance device includes a first ferromagnetic layer formed of ferromagnetic material, a non-magnetic insulative tunnel barrier layer coupled to the first ferromagnetic layer, a second ferromagnetic layer formed of ferromagnetic material and coupled to the tunnel barrier layer, and an anti-ferromagnetic layer formed of anti-ferromagnetic material. The second ferromagnetic layer is provided between the tunnel barrier layer and the anti-ferromagnetic layer. A perpendicular line from an optional position of the surface of the second ferromagnetic layer passes through at least two of the crystal grains of the second ferromagnetic layer.
    Type: Grant
    Filed: September 19, 2003
    Date of Patent: March 6, 2007
    Assignee: NEC Corporation
    Inventors: Ken-ichi Shimura, Atsushi Kamijo, Yoshiyuki Fukumoto, Kaoru Mori
  • Publication number: 20060056114
    Abstract: A magneto-resistance device is composed of an anti-ferromagnetic layer (5), a pinned ferromagnetic layer (20), a tunnel insulating layer (9) and a free ferromagnetic layer (21). The pinned ferromagnetic layer (20) is connected to the anti-ferromagnetic layer (5) and has a fixed spontaneous magnetization. The tunnel insulating layer (9) is connected to the pinned ferromagnetic layer (20) and is non-magnetic. The free ferromagnetic layer (21) is connected to the tunnel insulating layer (9) and has a reversible free spontaneous magnetization. The pinned ferromagnetic layer (20) has a first composite magnetic layer (6) to prevent at lest one component of the anti-ferromagnetic layer (5) from diffusing into tunnel insulating layer (9).
    Type: Application
    Filed: December 16, 2003
    Publication date: March 16, 2006
    Inventors: Yoshiyuki Fukumoto, Ken-ichi Shimura, Atsushi Kamijo
  • Publication number: 20050219769
    Abstract: The heat resistance of a magnetic resistance device utilizing the TMR effect is improved. Also, the Neel effect of the magnetic resistance device utilizing the TMR effect is restrained. The magnetic resistance device includes a first ferromagnetic layer formed of ferromagnetic material, a non-magnetic insulative tunnel barrier layer coupled to the first ferromagnetic layer, a second ferromagnetic layer formed of ferromagnetic material and coupled to the tunnel barrier layer, and an anti-ferromagnetic layer formed of anti-ferromagnetic material. The second ferromagnetic layer is provided between the tunnel barrier layer and the anti-ferromagnetic layer. A perpendicular line from an optional position of the surface of the second ferromagnetic layer passes through at least two of the crystal grains of the second ferromagnetic layer.
    Type: Application
    Filed: September 19, 2003
    Publication date: October 6, 2005
    Inventors: Ken-ichi Shimura, Atsushi Kamijo, Yoshiyuki Fukumoto, Kaoru Mori
  • Patent number: 6914257
    Abstract: In accordance with a method of producing an MR (MagnetoResistive) device including a ferromagnetic tunnel junction made up of a first ferromagnetic layer, an insulation layer formed on the first ferromagnetic layer and a second ferromagnetic layer formed on the insulation layer, a metal or a semiconductor is deposited on the first ferromagnetic layer. The metal or the semiconductor is then caused to react to oxygen of a ground level to become an oxide layer, which is the oxide of the metal or that of the semiconductor. Subsequently, the oxide layer is caused to react to oxygen of an excitation level to form the insulation layer. The second ferromagnetic layer is formed on the insulation layer.
    Type: Grant
    Filed: April 16, 2002
    Date of Patent: July 5, 2005
    Assignee: NEC Corporation
    Inventors: Ken-ichi Shimura, Hisanao Tsuge, Atsushi Kamijo, Tsutomu Mitsuzuka, Yoshiyuki Fukumoto
  • Publication number: 20040145850
    Abstract: A magnetoresistance device is provided for improving thermal stability of a magnetoresistance element by preventing interdiffusion between a conductor (such as a via and an interconnection) for connecting the magnetoresistance element to another element and layers constituting the magnetoresistance element. A magnetoresistance device is composed of a magnetoresistance element, a non-magnetic conductor providing electrical connection between said magnetoresistance element to another element, and a diffusion barrier structure disposed between said conductor and said magnetoresistance element, the magnetoresistance element including a free ferromagnetic layer having reversible spontaneous magnetization, a fixed ferromagnetic layer having fixed spontaneous magnetization, and a tunnel dielectric layer disposed between said free and fixed ferroelectric layer.
    Type: Application
    Filed: October 31, 2003
    Publication date: July 29, 2004
    Applicant: NEC CORPORATION
    Inventors: Yoshiyuki Fukumoto, Ken-ichi Shimura, Atsushi Kamijo
  • Publication number: 20030008416
    Abstract: In accordance with a method of producing an MR (MagnetoResistive) device including a ferromagnetic tunnel junction made up of a first ferromagnetic layer, an insulation layer formed on the first ferromagnetic layer and a second ferromagnetic layer formed on the insulation layer, a metal or a semiconductor is deposited on the first ferromagnetic layer. The metal or the semiconductor is then caused to react to oxygen of a ground level to become an oxide layer, which is the oxide of the metal or that of the semiconductor. Subsequently, the oxide layer is caused to react to oxygen of an excitation level to form the insulation layer. The second ferromagnetic layer is formed on the insulation layer.
    Type: Application
    Filed: April 16, 2002
    Publication date: January 9, 2003
    Applicant: NEC CORPORATION
    Inventors: Ken-Ichi Shimura, Hisanao Tsuge, Atsushi Kamijo, Tsutomu Mitsuzuka, Yoshiyuki Fukumoto