Patents by Inventor Mizue Ishikawa

Mizue Ishikawa 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: 9520171
    Abstract: A resistive change memory according to an embodiment includes: a memory cell including a resistive change element comprising a first and second terminals, and a semiconductor element, the semiconductor element including a first semiconductor layer of a first conductivity type, a second semiconductor layer of the first conductivity type, and a third semiconductor layer of a second conductivity type that is different from the first conductivity type, the third semiconductor layer being disposed between the first semiconductor layer and the second semiconductor layer, the first semiconductor layer being connected to the second terminal of the resistive change element; and a read unit configured to perform a read operation by applying a first read voltage between the first terminal and the second semiconductor layer, and then applying a second read voltage that is lower than the first read voltage between the first terminal and the second semiconductor layer.
    Type: Grant
    Filed: August 21, 2015
    Date of Patent: December 13, 2016
    Assignee: KABUSHIKI KAISHA TOSHIBA
    Inventors: Tomoaki Inokuchi, Mizue Ishikawa, Hideyuki Sugiyama, Yoshiaki Saito, Tetsufumi Tanamoto
  • Publication number: 20160276007
    Abstract: A spin transistor memory according to an embodiment includes: a first semiconductor region, a second semiconductor region, and a third semiconductor region, each being of a first conductivity type and disposed in a semiconductor layer; a first gate disposed above the semiconductor layer between the first semiconductor region and the second semiconductor region; a second gate disposed above the semiconductor layer between the second semiconductor region and the third semiconductor region; and a first ferromagnetic layer, a second ferromagnetic layer, and a third ferromagnetic layer disposed on the first semiconductor region, the second semiconductor region, and the third semiconductor region respectively.
    Type: Application
    Filed: March 8, 2016
    Publication date: September 22, 2016
    Applicant: Kabushiki Kaisha Toshiba
    Inventors: Hideyuki SUGIYAMA, Mizue ISHIKAWA, Tomoaki INOKUCHI, Yoshiaki SAITO
  • Publication number: 20160196861
    Abstract: A magnetic memory includes a magnetoresistive device and a load resistance unit. The magnetoresistive device has a first resistance state and a second resistance state and includes a first ferromagnetic layer and a second ferromagnetic layer. The load resistance unit is electrically connected to the magnetoresistive device. The load resistance unit is in a first state and a second state. Differential resistance of the load resistance unit at the second state is lower than differential resistance of the load resistance unit at the first state.
    Type: Application
    Filed: March 11, 2016
    Publication date: July 7, 2016
    Applicant: Kabushiki Kaisha Toshiba
    Inventors: Hideyuki SUGIYAMA, Tetsufumi Tanamoto, Mizue Ishikawa, Tomoaki Inokuchi, Yoshiaki Saito
  • Publication number: 20160078913
    Abstract: A magnetic memory according to an embodiment includes: a multilayer structure including a semiconductor layer and a first ferromagnetic layer; a first wiring line electrically connected to the semiconductor layer; a second wiring line electrically connected to the first ferromagnetic layer; and a voltage applying unit electrically connected between the first wiring line and the second wiring line to apply a first voltage between the semiconductor layer and the first ferromagnetic layer during a write operation, a magnetization direction of the first ferromagnetic layer being switchable by applying the first voltage.
    Type: Application
    Filed: November 23, 2015
    Publication date: March 17, 2016
    Applicant: Kabushiki Kaisha Toshiba
    Inventors: Tomoaki INOKUCHI, Mizue ISHIKAWA, Hideyuki SUGIYAMA, Tetsufumi TANAMOTO, Akira TAKASHIMA, Yoshiaki SAITO
  • Patent number: 9230625
    Abstract: A magnetic memory according to an embodiment includes: a multilayer structure including a semiconductor layer and a first ferromagnetic layer; a first wiring line electrically connected to the semiconductor layer; a second wiring line electrically connected to the first ferromagnetic layer; and a voltage applying unit electrically connected between the first wiring line and the second wiring line to apply a first voltage between the semiconductor layer and the first ferromagnetic layer during a write operation, a magnetization direction of the first ferromagnetic layer being switchable by applying the first voltage.
    Type: Grant
    Filed: March 11, 2014
    Date of Patent: January 5, 2016
    Assignee: KABUSHIKI KAISHA TOSHIBA
    Inventors: Tomoaki Inokuchi, Mizue Ishikawa, Hideyuki Sugiyama, Tetsufumi Tanamoto, Akira Takashima, Yoshiaki Saito
  • Publication number: 20150357016
    Abstract: A resistive change memory according to an embodiment includes: a memory cell including a resistive change element comprising a first and second terminals, and a semiconductor element, the semiconductor element including a first semiconductor layer of a first conductivity type, a second semiconductor layer of the first conductivity type, and a third semiconductor layer of a second conductivity type that is different from the first conductivity type, the third semiconductor layer being disposed between the first semiconductor layer and the second semiconductor layer, the first semiconductor layer being connected to the second terminal of the resistive change element; and a read unit configured to perform a read operation by applying a first read voltage between the first terminal and the second semiconductor layer, and then applying a second read voltage that is lower than the first read voltage between the first terminal and the second semiconductor layer.
    Type: Application
    Filed: August 21, 2015
    Publication date: December 10, 2015
    Applicant: KABUSHIKI KAISHA TOSHIBA
    Inventors: Tomoaki INOKUCHI, Mizue ISHIKAWA, Hideyuki SUGIYAMA, Yoshiaki SAITO, Tetsufumi TANAMOTO
  • Publication number: 20150311305
    Abstract: An MOSFET according to an embodiment includes: a source and drain electrodes each including a magnetic layer; a gate insulating film; and a gate electrode provided on the gate insulating film, a junction resistance on a source electrode side being greater than that on a drain electrode side, when the MOSFET is of n-channel type, the source and drain electrodes contain a magnetic material in which a gap energy between a Fermi surface and a valence band maximum is greater than that between the Fermi surface and a conduction band minimum, and when the spin-transfer-torque switching MOSFET is of p-channel type, the source and drain electrodes containing a magnetic material in which a gap energy between a Fermi surface and a valence band maximum is less than that between the Fermi surface and a conduction band minimum.
    Type: Application
    Filed: July 7, 2015
    Publication date: October 29, 2015
    Applicant: KABUSHIKI KAISHA TOSHIBA
    Inventors: Mizue ISHIKAWA, Tomoaki INOKUCHI, Hideyuki SUGIYAMA, Tetsufumi TANAMOTO, Yoshiaki SAITO
  • Patent number: 9112139
    Abstract: A spin transistor according to an embodiment includes: a first magnetic layer formed above a substrate and serving as one of a source and a drain; an insulating film having a lower face facing to an upper face of the first magnetic layer, an upper face opposed to the lower face, and a side face different from the lower and upper faces, the insulating film being formed on the upper face of the first magnetic layer and serving as a channel; a second magnetic layer formed on the upper face of the insulating film and serving as the other one of the source and the drain; a gate electrode formed along the side face of the insulating film; and a gate insulating film located between the gate electrode and the side face of the insulating film.
    Type: Grant
    Filed: June 18, 2012
    Date of Patent: August 18, 2015
    Assignee: KABUSHIKI KAISHA TOSHIBA
    Inventors: Tomoaki Inokuchi, Takao Marukame, Tetsufumi Tanamoto, Hideyuki Sugiyama, Mizue Ishikawa, Yoshiaki Saito
  • Patent number: 9112131
    Abstract: A spin MOSFET includes a first ferromagnetic layer having a fixed magnetization direction, a first tunnel barrier, a second ferromagnetic layer having a variable magnetization direction, and a nonmagnetic semiconductor layer provided in that order on a substrate. The nonmagnetic semiconductor layer has lower and upper faces and a side faces serving as a channel. A third ferromagnetic layer having a fixed magnetization direction is provided on the upper face of the nonmagnetic semiconductor layer, wherein the magnetization direction of each of the first to third ferromagnetic layers is in parallel or antiparallel to a direction from the third ferromagnetic layer to the first ferromagnetic layer. A nonmagnetic layer is provided on the third ferromagnetic layer, and a gate insulating film and gate electrode are provided in that order on the side face of the nonmagnetic semiconductor layer.
    Type: Grant
    Filed: December 13, 2013
    Date of Patent: August 18, 2015
    Assignee: KABUSHIKI KAISHA TOSHIBA
    Inventors: Yoshiaki Saito, Hideyuki Sugiyama, Tomoaki Inokuchi, Takao Marukame, Mizue Ishikawa
  • Patent number: 8981436
    Abstract: A stacked structure according to an embodiment includes: a semiconductor layer; a first layer formed on the semiconductor layer, the first layer containing at least one element selected from Zr, Ti, and Hf, the first layer being not thinner than a monoatomic layer and not thicker than a pentatomic layer; a tunnel barrier layer formed on the first layer; and a magnetic layer formed on the tunnel barrier layer.
    Type: Grant
    Filed: September 30, 2013
    Date of Patent: March 17, 2015
    Assignee: Kabushiki Kaisha Toshiba
    Inventors: Yoshiaki Saito, Tomoaki Inokuchi, Mizue Ishikawa, Hideyuki Sugiyama, Tetsufumi Tanamoto
  • Patent number: 8958239
    Abstract: One embodiment provides a magnetic memory element, including: a first ferromagnetic layer whose magnetization is variable; a second ferromagnetic layer which has a first band split into a valence band and a conduction band and a second band being continuous at least from the valence band to the conduction band; and a nonmagnetic layer provided between the first ferromagnetic layer and the second ferromagnetic layer.
    Type: Grant
    Filed: June 26, 2012
    Date of Patent: February 17, 2015
    Assignee: Kabushiki Kaisha Toshiba
    Inventors: Tomoaki Inokuchi, Takao Marukame, Mizue Ishikawa, Hideyuki Sugiyama, Masahiko Nakayama, Tatsuya Kishi, Hiroaki Yoda, Yoshiaki Saito
  • Publication number: 20140301136
    Abstract: A magnetic memory according to an embodiment includes: a multilayer structure including a semiconductor layer and a first ferromagnetic layer; a first wiring line electrically connected to the semiconductor layer; a second wiring line electrically connected to the first ferromagnetic layer; and a voltage applying unit electrically connected between the first wiring line and the second wiring line to apply a first voltage between the semiconductor layer and the first ferromagnetic layer during a write operation, a magnetization direction of the first ferromagnetic layer being switchable by applying the first voltage.
    Type: Application
    Filed: March 11, 2014
    Publication date: October 9, 2014
    Applicant: KABUSHIKI KAISHA TOSHIBA
    Inventors: Tomoaki INOKUCHI, Mizue ISHIKAWA, Hideyuki SUGIYAMA, Tetsufumi TANAMOTO, Akira TAKASHIMA, Yoshiaki SAITO
  • Publication number: 20140291744
    Abstract: A spin FET of an aspect of the present invention includes source/drain regions, a channel region between the source/drain regions, and a gate electrode above the channel region. Each of the source/drain regions includes a stack structure which is comprised of a low work function material and a ferromagnet. The low work function material is a non-oxide which is comprised of one of Mg, K, Ca and Sc, or an alloy which includes the non-oxide of 50 at % or more.
    Type: Application
    Filed: June 10, 2014
    Publication date: October 2, 2014
    Applicant: Kabushiki Kaisha Toshiba
    Inventors: Yoshiaki SAITO, Hideyuki Sugiyama, Tomoaki Inokuchi, Mizue Ishikawa
  • Patent number: 8847288
    Abstract: A spin transistor according to an embodiment includes: a semiconductor layer including a p+-region and an n+-region located at a distance from each other, and an i-region located between the p+-region and the n+-region; a first electrode located on the p+-region, the first electrode including a first ferromagnetic layer; a second electrode located on the n+-region, the second electrode including a second ferromagnetic layer; and a gate located on at least the i-region.
    Type: Grant
    Filed: January 25, 2013
    Date of Patent: September 30, 2014
    Assignee: Kabushiki Kaisha Toshiba
    Inventors: Tomoaki Inokuchi, Mizue Ishikawa, Hideyuki Sugiyama, Yoshiaki Saito
  • Publication number: 20140117427
    Abstract: A stacked structure according to an embodiment includes: a semiconductor layer; a first layer formed on the semiconductor layer, the first layer containing at least one element selected from Zr, Ti, and Hf, the first layer being not thinner than a monoatomic layer and not thicker than a pentatomic layer; a tunnel barrier layer formed on the first layer; and a magnetic layer formed on the tunnel barrier layer.
    Type: Application
    Filed: September 30, 2013
    Publication date: May 1, 2014
    Applicant: Kabushiki Kaisha Toshiba
    Inventors: Yoshiaki SAITO, Tomoaki Inokuchi, Mizue Ishikawa, Hideyuki Sugiyama, Tetsufumi Tanamoto
  • Publication number: 20140097474
    Abstract: A spin MOSFET includes a first ferromagnetic layer having a fixed magnetization direction, a first tunnel barrier, a second ferromagnetic layer having a variable magnetization direction, and a nonmagnetic semiconductor layer provided in that order on a substrate. The nonmagnetic semiconductor layer has lower and upper faces and a side faces serving as a channel. A third ferromagnetic layer having a fixed magnetization direction is provided on the upper face of the nonmagnetic semiconductor layer, wherein the magnetization direction of each of the first to third ferromagnetic layers is in parallel or antiparallel to a direction from the third ferromagnetic layer to the first ferromagnetic layer. A nonmagnetic layer is provided on the third ferromagnetic layer, and a gate insulating film and gate electrode are provided in that order on the side face of the nonmagnetic semiconductor layer.
    Type: Application
    Filed: December 13, 2013
    Publication date: April 10, 2014
    Applicant: Kabushiki Kaisha Toshiba
    Inventors: Yoshiaki Saito, Hideyuki Sugiyama, Tomoaki Inokuchi, Takao Marukame, Mizue Ishikawa
  • Patent number: 8637946
    Abstract: A spin MOSFET includes: a first ferromagnetic layer provided on a semiconductor substrate, and having a fixed magnetization direction perpendicular to a film plane; a semiconductor layer provided on the first ferromagnetic layer, including a lower face opposed to the upper face of the first ferromagnetic layer, an upper face opposed to the lower face, and side faces different from the lower and upper faces; a second ferromagnetic layer provided on the upper face of the semiconductor layer, and having a variable magnetization direction perpendicular to a film plane; a first tunnel barrier provided on the second ferromagnetic layer; a third ferromagnetic layer provided on the first tunnel barrier; a gate insulating film provided on the side faces of the semiconductor layer; and a gate electrode provided on the side faces of the semiconductor layer with the gate insulating film being interposed therebetween.
    Type: Grant
    Filed: September 9, 2011
    Date of Patent: January 28, 2014
    Assignee: Kabushiki Kaisha Toshiba
    Inventors: Yoshiaki Saito, Hideyuki Sugiyama, Tomoaki Inokuchi, Takao Marukame, Mizue Ishikawa
  • Patent number: 8618590
    Abstract: A spin transistor includes a first ferromagnetic layer, a second ferromagnetic layer, a semiconductor layer between the first and second ferromagnetic layers, and a gate electrode on or above a surface of the semiconductor layer, the surface being between the first and second ferromagnetic layers. The first ferromagnetic layer comprises a ferromagnet which has a first minority spin band located at a high energy side and a second minority spin band located at a low energy side, and has a Fermi level in an area of the high energy side higher than a middle of a gap between the first and second minority spin bands.
    Type: Grant
    Filed: September 17, 2009
    Date of Patent: December 31, 2013
    Assignee: Kabushiki Kaisha Toshiba
    Inventors: Tomoaki Inokuchi, Takao Marukame, Mizue Ishikawa, Hideyuki Sugiyama, Yoshiaki Saito
  • Patent number: 8611143
    Abstract: A memory circuit according to an embodiment includes: a first transistor including a first source/drain electrode, a second source/drain electrode, and a first gate electrode; a second transistor including a third source/drain electrode connected to the second source/drain electrode, a fourth source/drain electrode, and a second gate electrode; a third transistor and a fourth transistor forming an inverter circuit, the third transistor including a fifth source/drain electrode, a sixth source/drain electrode, and a third gate electrode connected to the second source/drain electrode, the fourth transistor including a seventh source/drain electrode connected to the sixth source/drain electrode, an eighth source/drain electrode, and a fourth gate electrode connected to the second source/drain electrode; and an output terminal connected to the sixth source/drain electrode.
    Type: Grant
    Filed: February 23, 2012
    Date of Patent: December 17, 2013
    Assignee: Kabushiki Kaisha Toshiba
    Inventors: Hideyuki Sugiyama, Masato Oda, Shinobu Fujita, Tetsufumi Tanamoto, Mizue Ishikawa, Takao Marukame, Tomoaki Inokuchi, Yoshiaki Saito
  • Patent number: 8576601
    Abstract: One embodiment provides a content addressable memory, including: a pair of spin MOSFETs including: a first spin MOSFET whose magnetization state is set in accordance with stored data; and a second spin MOSFET whose magnetization state is set in accordance with the stored data, the second spin MOSFET being connected in parallel with the first spin MOSFET; a first wiring configured to apply a gate voltage so that any one of the first spin MOSFET and the second spin MOSFET becomes electrically conductive in accordance with search data; and a second wiring configured to apply a current to both of the first spin MOSFET and the second spin MOSFET.
    Type: Grant
    Filed: February 23, 2012
    Date of Patent: November 5, 2013
    Assignee: Kabushiki Kaisha Toshiba
    Inventors: Takao Marukame, Tomoaki Inokuchi, Hideyuki Sugiyama, Mizue Ishikawa, Yoshiaki Saito, Atsuhiro Kinoshita, Kosuke Tatsumura