Patents by Inventor Yoshiaki Asao
Yoshiaki Asao 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: 20130058161Abstract: According to one embodiment, a memory device includes: a first signal line; a second signal line; a transistor; a first memory region; and a second memory region. The transistor controls a conduction of each of a current flowing between the first and the second signal lines and an opposite current. The first memory region has a first magnetic tunnel junction element. A magnetization direction thereof becomes parallel when a current flows in one direction, and the magnetization direction becomes antiparallel when a current in another direction. The second memory region has a second magnetic tunnel junction element. A magnetization direction thereof becomes parallel when a current flows in one direction, and becomes antiparallel when a current flows in another first direction.Type: ApplicationFiled: March 19, 2012Publication date: March 7, 2013Applicant: KABUSHIKI KAISHA TOSHIBAInventors: Takaya YAMANAKA, Susumu SHUTO, Yoshiaki ASAO
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Publication number: 20130001506Abstract: According to one embodiment, a resistance change memory includes resistance change elements, vias and sidewall insulating layers, the elements and the vias provided alternately in a first direction and a second direction orthogonal to the first direction, and the sidewall insulating layers provided on sidewalls of the elements. The elements are provided in a lattice pattern having a constant pitch. A thickness of each of the sidewall insulating layers in a direction orthogonal to the sidewalls is a value for contacting the sidewall insulating layers each other or more to form holes between the sidewall insulating layers. The vias are provided in the holes respectively.Type: ApplicationFiled: January 23, 2012Publication date: January 3, 2013Inventors: Motoyuki SATO, Yoshiaki Asao, Takashi Obara, Takashi Nakazawa
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Patent number: 8314464Abstract: First semiconductor layers are in source/drain regions on the semiconductor substrate. A second semiconductor layer comprises first portions on the first semiconductor layers and a second portion in a linear form in a channel region between the source/drain regions. A gate electrode is around the second portion of the second semiconductor layer via an insulating film. A film thickness of the second portion of the second semiconductor layer is smaller than a film thickness of the first portion of the second semiconductor layer.Type: GrantFiled: February 4, 2010Date of Patent: November 20, 2012Assignee: Kabushiki Kaisha ToshibaInventors: Masayoshi Iwayama, Yoshiaki Asao, Takeshi Kajiyama
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Publication number: 20120286339Abstract: A memory includes a semiconductor substrate. Magnetic tunnel junction elements are provided above the semiconductor substrate. Each of the magnetic tunnel junction elements stores data by a change in a resistance state, and the data is rewritable by a current. Cell transistors are provided on the semiconductor substrate. Each of the cell transistors is in a conductive state when the current is applied to the corresponding magnetic tunnel junction element. Gate electrodes are included in the respective cell transistors. Each of the gate electrodes controls the conductive state of the corresponding cell transistor. In active areas, the cell transistors are provided, and the active areas extend in an extending direction of intersecting the gate electrodes at an angle of (90-a tan(?)) degrees.Type: ApplicationFiled: March 14, 2012Publication date: November 15, 2012Applicant: KABUSHIKI KAISHA TOSHIBAInventor: Yoshiaki ASAO
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Patent number: 8309950Abstract: First semiconductor layers are in source/drain regions on the semiconductor substrate. A second semiconductor layer comprises first portions on the first semiconductor layers and a second portion on a channel region between the source/drain regions. Third semiconductor layers are on the first portions of the second semiconductor layer. A gate electrode is around the second portion of the second semiconductor layer via an insulating film. Contact plugs are in the first semiconductor layers, the first portions of the second semiconductor layers and the third semiconductor layers in the source/drain regions. A diameter of the contact plug in the second semiconductor layer is smaller than a diameter of the contact plug in the first and third semiconductor layers.Type: GrantFiled: February 4, 2010Date of Patent: November 13, 2012Assignee: Kabushiki Kaisha ToshibaInventors: Masayoshi Iwayama, Takeshi Kajiyama, Yoshiaki Asao
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Publication number: 20120281461Abstract: A memory includes MTJ elements. Active areas are separated to correspond to cell transistors, respectively, and extend in a first direction substantially orthogonal to an extending direction of gates of the cell transistors. The active areas are arranged in the first direction and constitute a plurality of active area columns. Two active area columns adjacent in a second direction are arranged to be half-pitch staggered in the first direction. As viewed from above surfaces of the active areas, each MTJ element is arranged to overlap with one end of each of the active areas. The first and second wirings extend while being folded back in a direction inclined with respect to the first and second directions in order to overlap with the MTJ elements alternately in the adjacent active area columns.Type: ApplicationFiled: March 13, 2012Publication date: November 8, 2012Applicant: KABUSHIKI KAISHA TOSHIBAInventor: Yoshiaki Asao
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Publication number: 20120273844Abstract: According to one embodiment, a magnetic random access memory includes a first gate electrode and a second gate electrode arranged at a predetermined pitch in a first direction, and extending in a second direction perpendicular to the first direction, a first magnetoresistive element formed above a portion between the first gate electrode and the second gate electrode, an electrode layer formed in a position higher than the first magnetoresistive element, and formed to have a distance which is a half of the pitch from the first magnetoresistive element in the first direction, an interconnection formed in a position higher than the electrode layer, and extending in the first direction, and a first via which connects the first magnetoresistive element and the interconnection, and the electrode layer and the interconnection, by using one conductive layer.Type: ApplicationFiled: September 19, 2011Publication date: November 1, 2012Applicant: KABUSHIKI KAISHA TOSHIBAInventors: Masayoshi IWAYAMA, Yoshiaki Asao
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Publication number: 20120261779Abstract: A magnetic random access memory which is a memory cell array including a magnetoresistive effect element having a fixed layer whose magnetization direction is fixed, a recording layer whose magnetization direction is reversible, and a non-magnetic layer provided between the fixed layer and the recording layer, wherein all conductive layers in the memory cell array arranged below the magnetoresistive effect element are formed of materials each containing an element selected from a group including W, Mo, Ta, Ti, Zr, Nb, Cr, Hf, V, Co, and Ni.Type: ApplicationFiled: February 9, 2012Publication date: October 18, 2012Inventors: Takeshi KAJIYAMA, Yoshiaki ASAO
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Publication number: 20120243296Abstract: A semiconductor memory device includes: plural word lines extending in a first direction; first to third bit lines extending in a second direction that intersects with the first direction; plural variable resistance elements each having a first terminal connected to either one of the first and third bit lines; plural active areas extending in a direction oblique to the first direction while intersecting with the first to third bit lines; plural select transistors provided on the active areas and each having a gate connected to a corresponding one of the word lines, and a current path whose one end is connected to a second terminal of a corresponding one of the variable resistance elements; and plural contact plugs each connecting the other end of the current path of a corresponding one of the select transistors to the second bit line.Type: ApplicationFiled: March 23, 2012Publication date: September 27, 2012Applicant: Kabushiki Kaisha ToshibaInventors: Toshiharu WATANABE, Yoshiaki ASAO
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Patent number: 8203193Abstract: A magnetic random access memory includes a magnetoresistive effect element which has a fixed layer, a recording layer and a non-magnetic layer provided between the fixed layer and the recording layer and in which the magnetization directions of the fixed layer and the recording layer are brought into a parallel state or an anti-parallel state in accordance with a direction of a current flowing between the fixed layer and the recording layer, a first contact which is connected to the recording layer and in which a contact area between the recording layer and the first contact is smaller than an area of the recording layer, and a cap layer which is provided between the first contact and the recording layer and which directly comes in contact with the first contact and which has a resistance higher than a resistance of the recording layer.Type: GrantFiled: June 17, 2011Date of Patent: June 19, 2012Assignee: Kabushiki Kaisha ToshibaInventors: Takeshi Kajiyama, Yoshiaki Asao, Akihiro Nitayama
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Patent number: 8164147Abstract: A magnetic random access memory includes a first bit line and a second bit line, a source line formed for a group having the first bit line and the second bit line, adjacent to the first bit line, and running in a first direction in which the first bit line and the second bit line run, a first magnetoresistive effect element connected to the first bit line, a second magnetoresistive effect element connected to the second bit line, a first transistor connected in series with the first magnetoresistive effect element, and a second transistor connected in series with the second magnetoresistive effect element. A first cell having the first magnetoresistive effect element and the first transistor and a second cell having the second magnetoresistive effect element and the second transistor are connected together to the source line.Type: GrantFiled: January 30, 2008Date of Patent: April 24, 2012Assignee: Kabushiki Kaisha ToshibaInventor: Yoshiaki Asao
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Patent number: 8111538Abstract: A semiconductor memory device includes a memory cell array having a plurality of memory cells which are set into low-resistance states/high-resistance states according to “0” data/“1” data. An allocation of the “0” data/“1” data and the low-resistance state/high-resistance state is switched when a power source is turned on.Type: GrantFiled: November 19, 2008Date of Patent: February 7, 2012Assignee: Kabushiki Kaisha ToshibaInventors: Keiji Hosotani, Yoshiaki Asao, Yoshihisa Iwata
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Patent number: 8111540Abstract: A semiconductor memory device includes first and second bit line provided in the same level layer above a semiconductor substrate, a first variable-resistance element disposed under the first bit line, having one terminal connected to one end of a current path of a first MOSFET, a second variable-resistance element disposed under the second bit line, and having one terminal connected to one end of a current path of a second MOSFET, a first interconnect layer connecting the first bit line to the other terminal of the first variable-resistance element, and connecting the first bit line to the other end of the current path of the second MOSFET, and a second interconnect layer connecting the second bit line to the other terminal of the second variable-resistance element, and connecting the second bit line to the other end of the current path of the first MOSFET.Type: GrantFiled: September 14, 2009Date of Patent: February 7, 2012Assignee: Kabushiki Kaisha ToshibaInventors: Yoshiaki Asao, Takeshi Kajiyama, Tsuneo Inaba
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Patent number: 8081505Abstract: A magnetoresistive element includes a stacked structure including a fixed layer having a fixed direction of magnetization, a recording layer having a variable direction of magnetization, and a nonmagnetic layer sandwiched between the fixed layer and the recording layer, a first protective film covering a circumferential surface of the stacked structure, and made of silicon nitride, and a second protective film covering a circumferential surface of the first protective film, and made of silicon nitride. A hydrogen content in the first protective film is not more than 4 at %, and a hydrogen content in the second protective film is not less than 6 at %.Type: GrantFiled: September 9, 2009Date of Patent: December 20, 2011Assignee: Kabushiki Kaisha ToshibaInventors: Takeshi Kajiyama, Yoshiaki Asao, Shigeki Takahashi, Minoru Amano, Kuniaki Sugiura
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Patent number: 8058080Abstract: A magnetic material of a magnetoresistive element is formed on a lower electrode. An upper electrode is formed on the magnetic material. A resist for nano-imprint lithography is formed on the upper electrode. A first pattern or a second pattern is formed in the resist by setting a first template or a second template into contact with the resist and curing the resist. The first template has the first pattern that corresponds to the magnetoresistive element and the lower electrode. The second template has the second pattern that corresponds to the magnetoresistive element and the upper electrode. The magnetic material and the lower electrode are patterned at the same time by using the resist having the first pattern, or the magnetic material and the upper electrode are patterned at the same time by using the resist having the second pattern.Type: GrantFiled: February 3, 2010Date of Patent: November 15, 2011Assignee: Kabushiki Kaisha ToshibaInventors: Takeshi Kajiyama, Yoshiaki Asao, Minoru Amano, Shigeki Takahashi, Masayoshi Iwayama, Kuniaki Sugiura
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Publication number: 20110254112Abstract: A semiconductor memory device includes a semiconductor substrate, and plural switching transistors provided on the semiconductor substrate. A contact plug is embedded between the adjacent two switching transistors described above, is insulated from gates of the adjacent two switching transistors, and is electrically connected to diffusion layers of the adjacent two switching transistors. An upper connector is formed on the contact plug, and an upper surface is at a position higher than upper surfaces of the switching transistors. A memory element is provided on the upper surface of the upper connector, and stores data. A wiring is provided on the memory element.Type: ApplicationFiled: January 27, 2011Publication date: October 20, 2011Applicant: KABUSHIKI KAISHA TOSHIBAInventors: Takaya YAMANAKA, Yoshiaki ASAO, Takeshi KAJIYAMA, Minoru AMANO, Masayoshi IWAYAMA, Kuniaki SUGIURA, Yukinori KOYAMA
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Publication number: 20110248365Abstract: A magnetic random access memory includes a magnetoresistive effect element which has a fixed layer, a recording layer and a non-magnetic layer provided between the fixed layer and the recording layer and in which the magnetization directions of the fixed layer and the recording layer are brought into a parallel state or an anti-parallel state in accordance with a direction of a current flowing between the fixed layer and the recording layer, a first contact which is connected to the recording layer and in which a contact area between the recording layer and the first contact is smaller than an area of the recording layer, and a cap layer which is provided between the first contact and the recording layer and which directly comes in contact with the first contact and which has a resistance higher than a resistance of the recording layer.Type: ApplicationFiled: June 17, 2011Publication date: October 13, 2011Inventors: Takeshi KAJIYAMA, Yoshiaki Asao, Akihiro Nitayama
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Publication number: 20110215382Abstract: According to one embodiment, a semiconductor memory device is disclosed. The device includes MOSFET1 and MOSFET2 arranged in a first direction, variable resistive element (hereafter R1) above MOSFET1 and MOSFET2, a lower end of the R1 being connected to drains of MOSFET1 and MOSFET2, MOSFET3 and MOSFET4 arranged in the first direction, variable resistive element (hereafter R2) above MOSFET3 and MOSFET4, and a lower end of the R2 being connected to drains of MOSFET3 and MOSFET4. The device further includes first wiring line extending in the first direction and connected to sources of MOSFET1 and MOSFET2, second wiring line extending in the first direction and connected to sources of MOSFET3 and MOSFET4, upper electrode connecting upper end of the R1 and upper end of the R2, and third wiring line extending in the first direction and connected to the upper electrode.Type: ApplicationFiled: February 25, 2011Publication date: September 8, 2011Applicant: KABUSHIKI KAISHA TOSHIBAInventors: Yoshiaki ASAO, Takeshi KAJIYAMA, Kuniaki SUGIURA
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Patent number: 8009456Abstract: A resistance change type memory includes first, second and third drive lines, a resistance change element having one end connected to the third drive line, a first diode having an anode connected to the first drive line and a cathode connected to other end of the first resistance change element, a second diode having an anode connected to other end of the first resistance change element and a cathode connected to the second drive line, and a driver/sinker which supplies a write current to the resistance change element. A write control circuit is arranged such that when first data is written, the write current is caused to flow in a direction from the first drive line to the third drive line, and when second data is written, the write current is caused to flow in a direction from the third drive line to the second drive line.Type: GrantFiled: January 8, 2009Date of Patent: August 30, 2011Assignee: Kabushiki Kaisha ToshibaInventors: Naoharu Shimomura, Yoshiaki Asao
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Patent number: 7990752Abstract: A semiconductor memory of an aspect of the present invention including a main bit line, a first and second sub-bit line, a first resistive memory element which has a first terminal being connected with the main bit line, a first select transistor which has one end of a first current path being connected with the second terminal of the first resistive memory element and the other end of the first current path being connected with the first sub-bit line, a second resistive memory element which has a third terminal being connected with the main bit line, and a second select transistor which has one end of a second current path being connected with the fourth terminal of the second resistive memory element and the other end of the second current path being connected with the second sub-bit line.Type: GrantFiled: June 2, 2009Date of Patent: August 2, 2011Assignee: Kabushiki Kaisha ToshibaInventor: Yoshiaki Asao