Patents by Inventor Susumu Shuto
Susumu Shuto 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: 9384829Abstract: A memory device includes n (n being an integer of 2 or more) resistance change films being series connected to each other. Each of the resistance change films is a superlattice film in which plural pairs of a first crystal layer made of a first compound and a second crystal layer made of a second compound are alternately stacked. An average composition of the entire resistance change film or an arrangement pitch of the first crystal layers and the second crystal layers are mutually different among the n resistance change films.Type: GrantFiled: March 20, 2013Date of Patent: July 5, 2016Assignee: KABUSHIKI KAISHA TOSHIBAInventors: Hironobu Furuhashi, Iwao Kunishima, Susumu Shuto, Yoshiaki Asao, Gaku Sudo
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Patent number: 9324406Abstract: According to one embodiment, a semiconductor memory device includes a memory cell and a control circuit. The memory cell is such that a ferroelectric film is provided as a gate dielectric film. When data is stored in the memory cell, the control circuit applies a first voltage to the gate dielectric film and thereafter applies a second voltage, whose amplitude is smaller than that of the first voltage and whose polarity is opposite to that of the first voltage.Type: GrantFiled: January 8, 2015Date of Patent: April 26, 2016Assignee: KABUSHIKI KAISHA TOSHIBAInventors: Susumu Shuto, Takayuki Okada, Iwao Kunishima
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Patent number: 9171886Abstract: A semiconductor memory device according to embodiments includes a semiconductor substrate and plural switching transistors provided on the semiconductor substrate. In the semiconductor memory device, a contact plug is embedded between adjacent two of the switching transistors, and is insulated from gates of the adjacent two switching transistors. The contact plug is also electrically connected to a source or a drain of each of the adjacent two switching transistors, and an upper surface of the contact plug is at a position higher than an upper surface of the switching transistors. A memory element is provided on the upper surface of the contact plug and stores data. A wiring is provided on the memory element.Type: GrantFiled: February 22, 2011Date of Patent: October 27, 2015Assignee: KABUSHIKI KAISHA TOSHIBAInventors: Hiroyuki Kanaya, Yukinori Koyama, Susumu Shuto, Kuniaki Sugiura
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Publication number: 20150117085Abstract: According to one embodiment, a semiconductor memory device includes a memory cell and a control circuit. The memory cell is such that a ferroelectric film is provided as a gate dielectric film. When data is stored in the memory cell, the control circuit applies a first voltage to the gate dielectric film and thereafter applies a second voltage, whose amplitude is smaller than that of the first voltage and whose polarity is opposite to that of the first voltage.Type: ApplicationFiled: January 8, 2015Publication date: April 30, 2015Applicant: KABUSHIKI KAISHA TOSHIBAInventors: Susumu SHUTO, Takayuki OKADA, Iwao KUNISHIMA
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Patent number: 8953359Abstract: According to one embodiment, a semiconductor memory device includes a memory cell and a control circuit. The memory cell is such that a ferroelectric film is provided as a gate dielectric film. When data is stored in the memory cell, the control circuit applies a first voltage to the gate dielectric film and thereafter applies a second voltage, whose amplitude is smaller than that of the first voltage and whose polarity is opposite to that of the first voltage.Type: GrantFiled: July 26, 2013Date of Patent: February 10, 2015Assignee: Kabushiki Kaisha ToshibaInventors: Susumu Shuto, Takayuki Okada, Iwao Kunishima
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Patent number: 8885396Abstract: According to one embodiment, a memory device includes: a first signal line; a second signal line; a transistor; a memory region; and a conductive region. The transistor controls a conduction of each of a current in a first direction flowing between the first line and the second line and a current in a second direction opposite to the first direction. The memory region has a first magnetic tunnel junction element which is connected between the first line and one end of the transistor, a magnetization direction of which becomes parallel when a current not less than a first parallel threshold value flows in the first direction, and the magnetization direction of which becomes antiparallel when a current not less than a first antiparallel threshold value flows in the second direction. The conductive region is connected between the second line and the other end of the transistor.Type: GrantFiled: March 19, 2012Date of Patent: November 11, 2014Assignee: Kabushiki Kaisha ToshibaInventors: Takaya Yamanaka, Susumu Shuto
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Patent number: 8861251Abstract: A semiconductor storage device includes a semiconductor substrate and an active area on the semiconductor substrate. A plurality of cell transistors are formed on the active area. A first bit line and a second bit line are paired with each other. A plurality of word lines intersect the first and second bit lines. A plurality of storage elements respectively has a first end electrically connected to a source or a drain of one of the cell transistors and a second end connected to the first or second bit line. Both of the first and second bit lines are connected to the same active area via the storage elements.Type: GrantFiled: March 19, 2012Date of Patent: October 14, 2014Assignee: Kabushiki Kaisha ToshibaInventor: Susumu Shuto
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Patent number: 8860103Abstract: A semiconductor memory device according to an embodiment includes: a plurality of magnetic tunnel junction elements arranged on a semiconductor substrate; and a plurality of selection transistors electrically connected to first ends of the plurality of magnetic tunnel junction elements. A plurality of first bit lines are respectively connected to the first ends of the magnetic tunnel junction elements via one or more of the selection transistors. A plurality of upper electrodes are respectively connected to second ends of the plurality of magnetic tunnel junction elements. A plurality of second bit lines are respectively connected to the second ends of the magnetic tunnel junction elements via the upper electrodes. The upper electrodes extend along the second bit lines, and one of the upper electrodes is commonly connected to the second ends of the plurality of magnetic tunnel junction elements arranged in an extending direction of the second bit lines.Type: GrantFiled: September 12, 2011Date of Patent: October 14, 2014Assignee: Kabushiki Kaisha ToshibaInventor: Susumu Shuto
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Patent number: 8854914Abstract: According to one embodiment, a memory cell, a word line, and a peripheral circuit are provided. In the memory cell, a ferroelectric film is provided for a gate insulating film. The word line is connected to a control gate electrode of the memory cell. In the peripheral circuit, ferroelectric films are provided for gate insulating films and the peripheral circuit is provided near the memory cell. Here, between the same conductive type transistors of the peripheral circuit, a channel impurity concentration of a transistor to which a driving voltage which drives the word line is applied is different from a channel impurity concentration of a transistor to which a voltage which is lower than the driving voltage is applied.Type: GrantFiled: July 29, 2013Date of Patent: October 7, 2014Assignee: Kabushiki Kaisha ToshibaInventor: Susumu Shuto
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Publication number: 20140254274Abstract: According to one embodiment, a semiconductor memory device includes a memory cell and a control circuit. The memory cell is such that a ferroelectric film is provided as a gate dielectric film. When data is stored in the memory cell, the control circuit applies a first voltage to the gate dielectric film and thereafter applies a second voltage, whose amplitude is smaller than that of the first voltage and whose polarity is opposite to that of the first voltage.Type: ApplicationFiled: July 26, 2013Publication date: September 11, 2014Applicant: KABUSHIKI KAISHA TOSHIBAInventors: Susumu SHUTO, Takayuki OKADA, Iwao KUNISHIMA
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Publication number: 20140254275Abstract: According to one embodiment, a memory cell, a word line, and a peripheral circuit are provided. In the memory cell, a ferroelectric film is provided for a gate insulating film. The word line is connected to a control gate electrode of the memory cell. In the peripheral circuit, ferroelectric films are provided for gate insulating films and the peripheral circuit is provided near the memory cell. Here, between the same conductive type transistors of the peripheral circuit, a channel impurity concentration of a transistor to which a driving voltage which drives the word line is applied is different from a channel impurity concentration of a transistor to which a voltage which is lower than the driving voltage is applied.Type: ApplicationFiled: July 29, 2013Publication date: September 11, 2014Inventor: Susumu SHUTO
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Patent number: 8804408Abstract: A semiconductor storage device according to the present embodiment includes a magnetic tunnel junction element capable of storing data according to a change in resistance state and rewriting the data using a current. A cell transistor is provided for the magnetic tunnel junction element and is placed in a conducting state when a current is allowed to flow through the magnetic tunnel junction element. A current limiter limits a current flowing through the cell transistor and the magnetic tunnel junction element upon data writing.Type: GrantFiled: September 13, 2011Date of Patent: August 12, 2014Assignee: Kabushiki Kaisha ToshibaInventor: Susumu Shuto
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Publication number: 20140185359Abstract: According to one embodiment, a memory device includes n (n being an integer of 2 or more) resistance change films being series connected to each other. Each of the resistance change films is a superlattice film in which a plurality of pairs of a first crystal layer made of a first compound and a second crystal layer made of a second compound are alternately stacked. Average composition of the entire resistance change film or arrangement pitch of the first crystal layers and the second crystal layers are mutually different among the n resistance change films.Type: ApplicationFiled: March 20, 2013Publication date: July 3, 2014Inventors: Hironobu FURUHASHI, Iwao KUNISHIMA, Susumu SHUTO, Yoshiaki ASAO, Gaku SUDO
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Patent number: 8724377Abstract: 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: GrantFiled: March 19, 2012Date of Patent: May 13, 2014Assignee: Kabushiki Kaisha ToshibaInventors: Takaya Yamanaka, Susumu Shuto, Yoshiaki Asao
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Patent number: 8503223Abstract: In a memory, the MTJ elements respectively have a first end electrically connected to any one of a source and a drain of one of the cell transistors. First bit lines each of which is electrically connected to the other one of the source and the drain of one of the cell transistors. Second bit lines each of which is electrically connected to a second end of one of the MTJ elements. Word lines each of which is electrically connected to a gate of one of the cell transistors or functions as a gate of one of the cell transistors. A plurality of the second bit lines correspond to one of the first bit lines. A plurality of the MTJ elements share the same word line and the same active area. The active area is continuously formed in an extending direction of the first and second bit lines.Type: GrantFiled: March 19, 2012Date of Patent: August 6, 2013Assignee: Kabushiki Kaisha ToshibaInventor: Susumu Shuto
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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: 20130058162Abstract: According to one embodiment, a memory device includes: a first signal line; a second signal line; a transistor; a memory region; and a conductive region. The transistor controls a conduction of each of a current in a first direction flowing between the first line and the second line and a current in a second direction opposite to the first direction. The memory region has a first magnetic tunnel junction element which is connected between the first line and one end of the transistor, a magnetization direction of which becomes parallel when a current not less than a first parallel threshold value flows in the first direction, and the magnetization direction of which becomes antiparallel when a current not less than a first antiparallel threshold value flows in the second direction. The conductive region is connected between the second line and the other end of the transistor.Type: ApplicationFiled: March 19, 2012Publication date: March 7, 2013Applicant: KABUSHIKI KAISHA TOSHIBAInventors: Takaya YAMANAKA, Susumu SHUTO
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Publication number: 20120314469Abstract: A semiconductor storage device includes a semiconductor substrate and an active area on the semiconductor substrate. A plurality of cell transistors are formed on the active area. A first bit line and a second bit line are paired with each other. A plurality of word lines intersect the first and second bit lines. A plurality of storage elements respectively has a first end electrically connected to a source or a drain of one of the cell transistors and a second end connected to the first or second bit line. Both of the first and second bit lines are connected to the same active area via the storage elements.Type: ApplicationFiled: March 19, 2012Publication date: December 13, 2012Applicant: KABUSHIKI KAISHA TOSHIBAInventor: Susumu SHUTO
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Publication number: 20120314494Abstract: In a memory, the MTJ elements respectively have a first end electrically connected to any one of a source and a drain of one of the cell transistors. First bit lines each of which is electrically connected to the other one of the source and the drain of one of the cell transistors. Second bit lines each of which is electrically connected to a second end of one of the MTJ elements. Word lines each of which is electrically connected to a gate of one of the cell transistors or functions as a gate of one of the cell transistors. A plurality of the second bit lines correspond to one of the first bit lines. A plurality of the MTJ elements share the same word line and the same active area. The active area is continuously formed in an extending direction of the first and second bit lines.Type: ApplicationFiled: March 19, 2012Publication date: December 13, 2012Applicant: KABUSHIKI KAISHA TOSHIBAInventor: Susumu Shuto
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Publication number: 20120243303Abstract: A semiconductor storage device according to the present embodiment includes a magnetic tunnel junction element capable of storing data according to a change in resistance state and rewriting the data using a current. A cell transistor is provided for the magnetic tunnel junction element and is placed in a conducting state when a current is allowed to flow through the magnetic tunnel junction element. A current limiter limits a current flowing through the cell transistor and the magnetic tunnel junction element upon data writing.Type: ApplicationFiled: September 13, 2011Publication date: September 27, 2012Applicant: KABUSHIKI KAISHA TOSHIBAInventor: Susumu Shuto