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).
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Patent number: 7742263Abstract: 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: GrantFiled: June 12, 2008Date of Patent: June 22, 2010Assignee: NEC CorporationInventors: Yoshiyuki Fukumoto, Ken-ichi Shimura, Atsushi Kamijo
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Publication number: 20080278867Abstract: 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: ApplicationFiled: June 12, 2008Publication date: November 13, 2008Applicant: NEC CORPORATIONInventors: Yoshiyuki FUKUMOTO, Ken-ichi SHIMURA, Atsushi KAMIJO
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Patent number: 7394626Abstract: 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: GrantFiled: October 31, 2003Date of Patent: July 1, 2008Assignee: NEC CorporationInventors: Yoshiyuki Fukumoto, Ken-ichi Shimura, Atsushi Kamijo
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Patent number: 7379280Abstract: 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: GrantFiled: December 16, 2003Date of Patent: May 27, 2008Assignee: NEC CorporationInventors: Yoshiyuki Fukumoto, Ken-ichi Shimura, Atsushi Kamijo
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Patent number: 7187525Abstract: 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: GrantFiled: September 19, 2003Date of Patent: March 6, 2007Assignee: NEC CorporationInventors: Ken-ichi Shimura, Atsushi Kamijo, Yoshiyuki Fukumoto, Kaoru Mori
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Publication number: 20060056114Abstract: 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: ApplicationFiled: December 16, 2003Publication date: March 16, 2006Inventors: Yoshiyuki Fukumoto, Ken-ichi Shimura, Atsushi Kamijo
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Publication number: 20050219769Abstract: 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: ApplicationFiled: September 19, 2003Publication date: October 6, 2005Inventors: Ken-ichi Shimura, Atsushi Kamijo, Yoshiyuki Fukumoto, Kaoru Mori
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Patent number: 6914257Abstract: 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: GrantFiled: April 16, 2002Date of Patent: July 5, 2005Assignee: NEC CorporationInventors: Ken-ichi Shimura, Hisanao Tsuge, Atsushi Kamijo, Tsutomu Mitsuzuka, Yoshiyuki Fukumoto
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Publication number: 20040145850Abstract: 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: ApplicationFiled: October 31, 2003Publication date: July 29, 2004Applicant: NEC CORPORATIONInventors: Yoshiyuki Fukumoto, Ken-ichi Shimura, Atsushi Kamijo
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Publication number: 20030008416Abstract: 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: ApplicationFiled: April 16, 2002Publication date: January 9, 2003Applicant: NEC CORPORATIONInventors: Ken-Ichi Shimura, Hisanao Tsuge, Atsushi Kamijo, Tsutomu Mitsuzuka, Yoshiyuki Fukumoto