Patents by Inventor Tomomasa Ueda
Tomomasa Ueda 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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Publication number: 20050199925Abstract: 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: ApplicationFiled: May 18, 2004Publication date: September 15, 2005Inventors: Takeshi Kajiyama, Tomomasa Ueda, Tatsuya Kishi, Hisanori Aikawa, Masatoshi Yoshikawa, Yoshiaki Asao, Hiroaki Yoda
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Patent number: 6934184Abstract: A highly reliable magnetic memory exhibits enhanced data-holding stability at high storage density in a storage layer of a magnetoresistive effect element used for memory cells. A magnetic memory includes a memory cell array having first wirings, second wirings intersecting the first wirings and memory cells each provided at an intersection area of the corresponding first and second wirings. Each memory cell is selected when the corresponding first and second wirings are selected.Type: GrantFiled: July 20, 2004Date of Patent: August 23, 2005Assignee: Kabushiki Kaisha ToshibaInventors: Minoru Amano, Tatsuya Kishi, Hiroaki Yoda, Yoshiaki Saito, Shigeki Takahashi, Tomomasa Ueda, Katsuya Nishiyama, Yoshiaki Asao, Yoshihisa Iwata
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Patent number: 6927468Abstract: A write line is covered with a yoke material. The recording layer of an MTJ element is exchange-coupled to the yoke material. The total magnetic volume ?Msi×ti of the recording layer of the MTJ element and a portion of the yoke material that is exchange-coupled to the recording layer is smaller than the magnetic volume ?Msi?×ti? of the remaining portion of the yoke material that covers the write line.Type: GrantFiled: March 6, 2003Date of Patent: August 9, 2005Assignee: Kabushiki Kaisha ToshibaInventors: Hiroaki Yoda, Yoshiaki Asao, Tomomasa Ueda, Junichi Miyamoto, Tatsuya Kishi, Minoru Amano, Takeshi Kajiyama, Hisanori Aikawa
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Publication number: 20050141148Abstract: It is possible to reduce writing current without causing fluctuation of the writing characteristic. A magnetic memory includes: a magnetoresistance effect element having a magnetization pinned layer whose magnetization direction is pinned, a storage layer whose magnetization direction is changeable, and a non-magnetic layer provided between the magnetization pinned layer and the storage layer; and a first wiring layer which is electrically connected to the magnetoresistance effect element and extends in a direction substantially perpendicular to a direction of an easy magnetization axis of the storage layer, an end face of the magnetoresistance effect element substantially perpendicular to the direction of the easy magnetization axis of the storage layer and an end face of the first wiring layer substantially perpendicular to the direction of the easy magnetization axis being positioned on the same plane.Type: ApplicationFiled: December 1, 2004Publication date: June 30, 2005Applicant: Kabushiki Kaisha ToshibaInventors: Hisanori Aikawa, Tomomasa Ueda, Tatsuya Kishi, Takeshi Kajiyama, Yoshiaki Asao, Hiroaki Yoda
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Patent number: 6909130Abstract: A recording layer of an MTJ element is constituted by using a high crystal magnetic anisotropic material. A write wiring used to write data into the MTJ element is covered with a magnetic layer, and the write wiring and the magnetic layer are exchange-coupled with each other. A sum of a magnetic volume of the magnetic layer at a part opposed to the recording layer of the MTJ element and that of the recording layer is set smaller than a magnetic volume of the magnetic layer at any other part.Type: GrantFiled: November 12, 2003Date of Patent: June 21, 2005Assignee: Kabushiki Kaisha ToshibaInventors: Hiroaki Yoda, Tomomasa Ueda, Hisanori Aikawa, Tatsuya Kishi, Takeshi Kajiyama, Yoshiaki Asao
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Patent number: 6900490Abstract: In a magnetic random access memory for generating an inductive magnetic flux by passing current into write wirings disposed closely to MTJ elements, whose resistance values varying depending on the magnetization array state of two magnetic layers of MTJ elements including two magnetic layers that hold a non-magnetic layer correspond to the stored information of “0”/“1”, and writing information by varying the magnetization direction of a free layer of the MTJ elements, the shape of the MTJ elements is warped so as to coincide substantially with the magnetic field curve generated from the write wirings.Type: GrantFiled: August 28, 2003Date of Patent: May 31, 2005Assignee: Kabushiki Kaisha ToshibaInventors: Yoshiaki Asao, Hiroaki Yoda, Minoru Amano, Tomomasa Ueda
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Publication number: 20050083745Abstract: A magnetic memory includes: a magnetoresistance effect element having a magnetic recording layer; a first writing wiring extending in a first direction on or below the magnetoresistance effect element, a center of gravity of an axial cross section of the wiring being apart from a center of thickness at the center of gravity, and the center of gravity being eccentric toward the magnetoresistance effect element; and a writing circuit configured to pass a current through the first writing wiring in order to record an information in the magnetic recording layer by a magnetic field generated by the current.Type: ApplicationFiled: November 5, 2004Publication date: April 21, 2005Applicant: Kabushiki Kaisha ToshibaInventors: Tatsuya Kishi, Minoru Amano, Yoshiaki Saito, Shigeki Takahashi, Katsuya Nishiyama, Yoshiaki Asao, Hiroaki Yoda, Tomomasa Ueda, Yoshihisa Iwata
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Patent number: 6879515Abstract: A magnetic memory device includes first wiring which runs in the first direction, second wiring which runs in the second direction, a magneto-resistance element which is arranged at an intersection between the first and second wirings, a first yoke main body which covers at least either of the lower surface and two side surfaces of the first wring, a second yoke main body which covers at least either of the upper surface and two side surfaces of the second wiring, first and second yoke tips which are arranged on two sides of the magneto-resistance element in the first direction at an interval from the magneto-resistance element, and third and fourth yoke tips which are arranged on two sides of the magneto-resistance element in the second direction at an interval from the magneto-resistance element.Type: GrantFiled: August 26, 2004Date of Patent: April 12, 2005Assignee: Kabushiki Kaisha ToshibaInventors: Hiroaki Yoda, Yoshiaki Asao, Tomomasa Ueda, Minoru Amano, Tatsuya Kishi, Keiji Hosotani, Junichi Miyamoto
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Patent number: 6873023Abstract: A write word line is disposed right under an MTJ element. The write word line extends in an X direction, and a lower surface of the line is coated with a yoke material which has a high permeability. A data selection line (read/write bit line) is disposed right on the MTJ element. A data selection line extends in a Y direction intersecting with the X direction, and an upper surface of the line is coated with the yoke material which has the high permeability. At a write operation time, a magnetic field generated by a write current flowing through a write word line B and data selection line functions on the MTJ element by the yoke material with good efficiency.Type: GrantFiled: April 18, 2003Date of Patent: March 29, 2005Assignee: Kabushiki Kaisha ToshibaInventors: Yoshiaki Asao, Yoshihisa Iwata, Yoshiaki Saito, Hiroaki Yoda, Tomomasa Ueda, Minoru Amano, Shigeki Takahashi, Tatsuya Kishi
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Publication number: 20050024930Abstract: A magnetic memory device includes first wiring which runs in the first direction, second wiring which runs in the second direction, a magneto-resistance element which is arranged at an intersection between the first and second wirings, a first yoke main body which covers at least either of the lower surface and two side surfaces of the first wring, a second yoke main body which covers at least either of the upper surface and two side surfaces of the second wiring, first and second yoke tips which are arranged on two sides of the magneto-resistance element in the first direction at an interval from the magneto-resistance element, and third and fourth yoke tips which are arranged on two sides of the magneto-resistance element in the second direction at an interval from the magneto-resistance element.Type: ApplicationFiled: August 26, 2004Publication date: February 3, 2005Inventors: Hiroaki Yoda, Yoshiaki Asao, Tomomasa Ueda, Minoru Amano, Tatsuya Kishi, Keiji Hosotani, Junichi Miyamoto
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Publication number: 20050018478Abstract: 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: ApplicationFiled: June 8, 2004Publication date: January 27, 2005Inventors: Toshihiko Nagase, Hiroaki Yoda, Masatoshi Yoshikawa, Tadashi Kai, Tatsuya Kishi, Hisanori Aikawa, Tomomasa Ueda
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Publication number: 20050020011Abstract: A method of manufacturing a magnetic memory device includes forming an insulation layer on a substrate, forming a lower electrode on the insulation layer, forming a magneto-resistive film on an upper surface of the lower electrode, the magneto-resistive film including an insulation barrier layer and a plurality of magnetic films stacked on both sides of the insulation barrier layer, stacking a mask layer on the magneto-resistive film, performing ion etching on the magneto-resistive film, using the mask layer as a mask, thereby forming a magneto-resistive element, forming an insulation film on upper surfaces of the mask, the magneto-resistive element and the lower electrode, and etching the insulation film with an ion beam such that a side surface of the magneto-resistive element is exposed.Type: ApplicationFiled: November 7, 2003Publication date: January 27, 2005Inventors: Kentaro Nakajima, Minoru Amano, Tomomasa Ueda, Shigeki Takahashi
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Publication number: 20040257866Abstract: A highly reliable magnetic memory exhibits enhanced data-holding stability at high storage density in a storage layer of a magnetoresistive effect element used for memory cells. A magnetic memory includes a memory cell array having first wirings, second wirings intersecting the first wirings and memory cells each provided at an intersection area of the corresponding first and second wirings. Each memory cell is selected when the corresponding first and second wirings are selected.Type: ApplicationFiled: July 20, 2004Publication date: December 23, 2004Applicant: KABUSHIKI KAISHA TOSHIBAInventors: Minoru Amano, Tatsuya Kishi, Hiroaki Yoda, Yoshiaki Saito, Shigeki Takahashi, Tomomasa Ueda, Katsuya Nishiyama, Yoshiaki Asao, Yoshihisa Iwata
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Patent number: 6831855Abstract: A magnetic memory includes: a magnetoresistance effect element having a magnetic recording layer; a first writing wiring extending in a first direction on or below the magnetoresistance effect element, a center of gravity of an axial cross section of the wiring being apart from a center of thickness at the center of gravity, and the center of gravity being eccentric toward the magnetoresistance effect element; and a writing circuit configured to pass a current through the first writing wiring in order to record an information in the magnetic recording layer by a magnetic field generated by the current.Type: GrantFiled: January 16, 2003Date of Patent: December 14, 2004Assignee: Kabushiki Kaisha ToshibaInventors: Tatsuya Kishi, Minoru Amano, Yoshiaki Saito, Shigeki Takahashi, Katsuya Nishiyama, Yoshiaki Asao, Hiroaki Yoda, Tomomasa Ueda, Yoshihisa Iwata
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Patent number: 6831857Abstract: A highly reliable magnetic memory exhibits enhanced data-holding stability at high storage density in a storage layer of a magnetoresistive effect element used for memory cells. A magnetic memory includes a memory cell array having first wirings, second wirings intersecting the first wirings and memory cells each provided at an intersection area of the corresponding first and second wirings. Each memory cell is selected when the corresponding first and second wirings are selected.Type: GrantFiled: December 27, 2002Date of Patent: December 14, 2004Assignee: Kabushiki Kaisha ToshibaInventors: Minoru Amano, Tatsuya Kishi, Hiroaki Yoda, Yoshiaki Saito, Shigeki Takahashi, Tomomasa Ueda, Katsuya Nishiyama, Yoshiaki Asao, Yoshihisa Iwata
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Publication number: 20040223382Abstract: There are provided at least one wire, a magnetoresistive effect element having a storage layer whose magnetization direction varies according to a current magnetic field generated by causing a current to flow in the wire, and first yokes provided so as to be spaced from at least one pair of opposed side faces of the magnetoresistive effect element to form a magnetic circuit in cooperation with the magnetoresistive effect element when a current is caused to flow in the wire. Each of the first yokes has at least two soft magnetic layers which are stacked via a non-magnetic layer.Type: ApplicationFiled: June 10, 2004Publication date: November 11, 2004Applicant: Kabushiki Kaisha ToshibaInventors: Yoshiaki Saito, Tomomasa Ueda, Tatsuya Kishi, Minoru Amano
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Patent number: 6807094Abstract: A magnetic memory includes a magnetoresistance effect element having a magnetic recording layer, a first wiring extending in a first direction on or below the magnetoresistance effect element, a covering layer provided on at least both sides of the first wiring, and a writing circuit configured to pass a current through the first wiring in order to record information in the magnetic recording layer by a magnetic field generated by the current. The covering layer is made of magnetic material and has a uniaxial anisotropy in the first direction, along which a magnetization of the covering layer occurs.Type: GrantFiled: February 3, 2004Date of Patent: October 19, 2004Assignee: Kabushiki Kaisha ToshibaInventors: Yoshiaki Saito, Katsuya Nishiyama, Shigeki Takahashi, Minoru Amano, Tomomasa Ueda, Hiroaki Yoda, Yoshiaki Asao, Yoshihisa Iwata, Tatsuya Kishi
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Publication number: 20040195602Abstract: A recording layer of an MTJ element is constituted by using a high crystal magnetic anisotropic material. A write wiring used to write data into the MTJ element is covered with a magnetic layer, and the write wiring and the magnetic layer are exchange-coupled with each other. A sum of a magnetic volume of the magnetic layer at a part opposed to the recording layer of the MTJ element and that of the recording layer is set smaller than a magnetic volume of the magnetic layer at any other part.Type: ApplicationFiled: November 12, 2003Publication date: October 7, 2004Inventors: Hiroaki Yoda, Tomomasa Ueda, Hisanori Aikawa, Tatsuya Kishi, Takeshi Kajiyama, Yoshiaki Asao
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Publication number: 20040188733Abstract: In a magnetic random access memory for generating an inductive magnetic flux by passing current into write wirings disposed closely to MTJ elements, whose resistance values varying depending on the magnetization array state of two magnetic layers of MTJ elements including two magnetic layers that hold a non-magnetic layer correspond to the stored information of “0”/“1”, and writing information by varying the magnetization direction of a free layer of the MTJ elements, the shape of the MT J elements is warped so as to coincide substantially with the magnetic field curve generated from the write wirings.Type: ApplicationFiled: August 28, 2003Publication date: September 30, 2004Inventors: Yoshiaki Asao, Hiroaki Yoda, Minoru Amano, Tomomasa Ueda
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Patent number: 6797536Abstract: A magnetic memory device includes first wiring which runs in the first direction, second wiring which runs in the second direction, a magneto-resistance element which is arranged at an intersection between the first and second wirings, a first yoke main body which covers at least either of the lower surface and two side surfaces of the first wring, a second yoke main body which covers at least either of the upper surface and two side surfaces of the second wiring, first and second yoke tips which are arranged on two sides of the magneto-resistance element in the first direction at an interval from the magneto-resistance element, and third and fourth yoke tips which are arranged on two sides of the magneto-resistance element in the second direction at an interval from the magneto-resistance element.Type: GrantFiled: February 2, 2004Date of Patent: September 28, 2004Assignee: Kabushiki Kaisha ToshibaInventors: Hiroaki Yoda, Yoshiaki Asao, Tomomasa Ueda, Minoru Amano, Tatsuya Kishi, Keiji Hosotani, Junichi Miyamoto