Patents by Inventor Takashi Izumida

Takashi Izumida 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: 9825100
    Abstract: According to one embodiment, a nonvolatile semiconductor memory device includes a plurality of conducting layers, a semiconductor layer, a variable resistive element, and a first wiring. The plurality of conducting layers are laminated in a first direction at predetermined pitches. The conducting layers extend in a second direction. The second direction is along the surface of the substrate. The semiconductor layer extends in the first direction. The variable resistive element is disposed at an intersection point between the plurality of conducting layers and the semiconductor layer. The first wiring is opposed to an inside of the semiconductor layer via a gate insulating film. The first wiring extends in the first direction. The semiconductor layer at least includes a first part and a second part. The first part is upward of the conducting layer on a lowermost layer. The second part is downward of the first part. The first part has a first length in a third direction.
    Type: Grant
    Filed: February 1, 2016
    Date of Patent: November 21, 2017
    Assignee: TOSHIBA MEMORY CORPORATION
    Inventors: Yuki Sekino, Takashi Izumida, Nobutoshi Aoki
  • Publication number: 20170263635
    Abstract: According to one embodiment, a semiconductor device includes a substrate; a stacked body provided on the substrate, the stacked body including a plurality of electrode layers stacked with an insulator interposed; a semiconductor body provided in the stacked body; and an insulating film. The semiconductor body includes a channel portion extending in a stacking direction of the stacked body, and a lower end portion of the semiconductor body provided between the channel portion and the substrate. The insulating film includes a charge storage film provided between the stacked body and the semiconductor body. A lower end portion of the insulating film surrounds the lower end portion of the semiconductor body. An upper surface of the lower end portion of the insulating film is provided at a lower height than an upper surface of the lower end portion of the semiconductor body in the stacking direction.
    Type: Application
    Filed: September 14, 2016
    Publication date: September 14, 2017
    Applicant: Kabushiki Kaisha Toshiba
    Inventors: Tatsufumi HAMADA, Hikari TAJIMA, Takashi IZUMIDA, Nobutoshi AOKI, Shinya NAITO, Takayuki KAKEGAWA, Takaya YAMANAKA
  • Patent number: 9748312
    Abstract: According to an embodiment, a semiconductor memory device comprises: a first semiconductor layer extending in a first direction; a first wiring line extending in a second direction intersecting the first direction; a variable resistance layer provided between these first wiring line and first semiconductor layer; and a first gate electrode extending in the first direction and facing the first semiconductor layer via a first insulating layer. In addition, this semiconductor memory device comprises a second gate electrode provided in the first direction with respect to the first wiring line, extending in the second direction in parallel to the first wiring line, and facing the first semiconductor layer. This second gate electrode faces the first semiconductor layer via a second insulating layer. Moreover, this second gate electrode faces the first gate electrode via the second insulating layer, the first semiconductor layer, and the first insulating layer.
    Type: Grant
    Filed: March 17, 2016
    Date of Patent: August 29, 2017
    Assignee: KABUSHIKI KAISHA TOSHIBA
    Inventors: Takashi Izumida, Hikari Tajima
  • Publication number: 20170236872
    Abstract: A semiconductor memory device according to an embodiment includes a memory cell array that includes a plurality of memory cells.
    Type: Application
    Filed: September 21, 2016
    Publication date: August 17, 2017
    Applicant: Kabushiki Kaisha Toshiba
    Inventors: Takahisa KANEMURA, Takashi Izumida
  • Publication number: 20170125482
    Abstract: According to an embodiment, a semiconductor memory device comprises: a first semiconductor layer extending in a first direction; a first wiring line extending in a second direction intersecting the first direction; a variable resistance layer provided between these first wiring line and first semiconductor layer; and a first gate electrode extending in the first direction and facing the first semiconductor layer via a first insulating layer. In addition, this semiconductor memory device comprises a second gate electrode provided in the first direction with respect to the first wiring line, extending in the second direction in parallel to the first wiring line, and facing the first semiconductor layer. This second gate electrode faces the first semiconductor layer via a second insulating layer. Moreover, this second gate electrode faces the first gate electrode via the second insulating layer, the first semiconductor layer, and the first insulating layer.
    Type: Application
    Filed: March 17, 2016
    Publication date: May 4, 2017
    Applicant: Kabushiki Kaisha Toshiba
    Inventors: Takashi IZUMIDA, Hikari TAJIMA
  • Publication number: 20170098763
    Abstract: A semiconductor memory device according to an embodiment includes: a plurality of first conductive lines stacked in a first direction above a semiconductor substrate and extending in a second direction; a second conductive line extending in the first direction; semiconductor layers arranged between the first conductive lines and the second conductive line and extending in the first direction; a conductive layer in contact with a bottom surface of the semiconductor layer with a first impurity of a first conductivity type; and variable resistance films arranged at intersections between the first conductive lines and the semiconductor layer, the semiconductor layer having a first semiconductor part arranged from the bottom surface of the semiconductor layer to a position equal to or lower than a bottom surface of the first conductive line at a lowermost layer in the first direction with a second impurity of a second conductivity type.
    Type: Application
    Filed: January 22, 2016
    Publication date: April 6, 2017
    Applicant: Kabushiki Kaisha Toshiba
    Inventors: Hikari TAJIMA, Takashi IZUMIDA
  • Publication number: 20170084329
    Abstract: According to an embodiment, a semiconductor memory device comprises: a first wiring line; a memory string connected to this first wiring line; and a plurality of second wiring lines connected to this memory string. In addition, this memory string comprises: a first semiconductor layer connected to the first wiring line; a plurality of second semiconductor layers connected to this first semiconductor layer; and a variable resistance element connected between this second semiconductor layer and the second wiring line. Moreover, of the first semiconductor layer and the plurality of second semiconductor layers, one includes a semiconductor of a first conductivity type, and the other includes a semiconductor of a second conductivity type.
    Type: Application
    Filed: March 15, 2016
    Publication date: March 23, 2017
    Applicant: Kabushiki Kaisha Toshiba
    Inventors: Hiroki TOKUHIRA, Hiroyoshi TANIMOTO, Takashi IZUMIDA
  • Publication number: 20170077180
    Abstract: A nonvolatile semiconductor memory device includes a memory cell array. The memory cell array includes conducting layers, semiconductor layers, variable resistance films, and first wirings. The conducting layers are laminated in a first direction perpendicular to a substrate, and extend in a second direction parallel to the substrate. The semiconductor layers extend in the first direction. The variable resistance films are disposed at intersection points of the conducting layers and the semiconductor layers. Each first wiring is opposed to the semiconductor layer via a gate insulating film. The first wirings extend in the first direction. Each variable resistance film has a first thickness at a first part. The first thickness is in a direction from the conducting layers to the semiconductor layer. The variable resistance film has a second thickness at a second part. The second part is far from the substrate more than the first part. The second thickness is smaller than the first thickness.
    Type: Application
    Filed: January 14, 2016
    Publication date: March 16, 2017
    Applicant: KABUSHIKI KAISHA TOSHIBA
    Inventors: Sanae ITO, Takashi IZUMIDA, Hikari TAJIMA
  • Patent number: 9595324
    Abstract: According to an embodiment, a semiconductor memory device comprises: a first wiring line; a memory string connected to this first wiring line; and a plurality of second wiring lines connected to this memory string. In addition, this memory string comprises: a first semiconductor layer connected to the first wiring line; a plurality of second semiconductor layers connected to this first semiconductor layer; and a variable resistance element connected between this second semiconductor layer and the second wiring line. Moreover, of the first semiconductor layer and the plurality of second semiconductor layers, one includes a semiconductor of a first conductivity type, and the other includes a semiconductor of a second conductivity type.
    Type: Grant
    Filed: March 15, 2016
    Date of Patent: March 14, 2017
    Assignee: KABUSHIKI KAISHA TOSHIBA
    Inventors: Hiroki Tokuhira, Hiroyoshi Tanimoto, Takashi Izumida
  • Publication number: 20170062523
    Abstract: According to one embodiment, a nonvolatile semiconductor memory device includes a plurality of conducting layers, a semiconductor layer, a variable resistive element, and a first wiring. The plurality of conducting layers are laminated in a first direction at predetermined pitches. The conducting layers extend in a second direction. The second direction is along the surface of the substrate. The semiconductor layer extends in the first direction. The variable resistive element is disposed at an intersection point between the plurality of conducting layers and the semiconductor layer. The first wiring is opposed to an inside of the semiconductor layer via a gate insulating film. The first wiring extends in the first direction. The semiconductor layer at least includes a first part and a second part. The first part is upward of the conducting layer on a lowermost layer. The second part is downward of the first part. The first part has a first length in a third direction.
    Type: Application
    Filed: February 1, 2016
    Publication date: March 2, 2017
    Applicant: KABUSHIKI KAISHA TOSHIBA
    Inventors: Yuki SEKINO, Takashi IZUMIDA, Nobutoshi AOKI
  • Patent number: 9570514
    Abstract: According to an embodiment, a semiconductor device includes two electrodes extending in a first direction, a semiconductor layer provided between the two electrodes, an insulating film disposed between the two electrodes. The two electrodes are arranged in a second direction intersecting the first direction. The semiconductor layer extends in a third direction orthogonal to the first direction and the second direction. The insulating film covers a side surface of the semiconductor layer opposite to one of the two electrodes. The semiconductor layer has a shape in a cross section perpendicular to the third direction such that a width in the first direction at a center of the cross section is narrower than a width, in the first direction, of the side surface.
    Type: Grant
    Filed: September 11, 2014
    Date of Patent: February 14, 2017
    Assignee: Kabushiki Kaisha Toshiba
    Inventors: Hikari Tajima, Masaki Kondo, Tsukasa Nakai, Takashi Izumida, Nobuaki Yasutake
  • Patent number: 9536894
    Abstract: According to an embodiment, a non-volatile memory device includes first electrodes arranged in a first direction, a second electrode disposed on a side of the first electrodes in the first direction, a semiconductor layer extending in the first direction through the first electrodes and the second electrode, and a memory film provided between the semiconductor layer and each of the first electrodes. The semiconductor layer includes crystal grains and has a first portion and a second portion, the first portion being adjacent to the first electrodes, and the second portion being adjacent to at least a part of the second electrode, wherein the first portion includes a larger crystal grain than a crystal grain in the second portion.
    Type: Grant
    Filed: February 11, 2015
    Date of Patent: January 3, 2017
    Assignee: Kabushiki Kaisha Toshiba
    Inventors: Hikari Tajima, Masaki Kondo, Tsukasa Nakai, Takashi Izumida, Hiroki Tokuhira
  • Patent number: 9536616
    Abstract: A non-volatile memory device includes a first electrode layer, a second electrode layer adjacent to the first electrode layer, a third electrode layer adjacent to the second electrode layer, a fourth electrode layer adjacent to the third electrode layer, and a channel body extending through the first electrode layer, the second electrode layer, the third electrode layer and the fourth electrode layer in a first direction. The device further includes a circuit electrically connected to the first electrode layer, the second electrode layer, the third electrode layer, the fourth electrode layer, and the channel body. The circuit providing the second electrode layer with a first potential, the third electrode layer with a second potential higher than the first potential, the fourth electrode layer with a third potential between the first potential and the second potential and the channel body with a potential rising in the first direction.
    Type: Grant
    Filed: December 15, 2015
    Date of Patent: January 3, 2017
    Assignee: Kabushiki Kaisha Toshiba
    Inventors: Hikari Tajima, Masaki Kondo, Tsukasa Nakai, Takashi Izumida, Nobutoshi Aoki
  • Publication number: 20160372481
    Abstract: A non-volatile memory device includes a first conductive layer of a first conductivity type and a second conductive layer of a second conductivity type on the first conductive layer. The second conductor layer has a surface opposite to the first conductive layer. The device includes a first electrode layer arranged with the second conductive layer in a first direction perpendicular to the surface of the second conductive layer, a first channel body extending through the first electrode layer in the first direction, and a charge storage layer between the first electrode layer and the first channel body. The device includes a first region of the first conductivity type between the first conductive layer and the first channel body, and a conductor arranged with the first electrode in a second direction parallel to the surface of the second conductive layer. The conductor is electrically connected to the second conductive layer.
    Type: Application
    Filed: December 3, 2015
    Publication date: December 22, 2016
    Applicant: Kabushiki Kaisha Toshiba
    Inventors: Takashi IZUMIDA, Masaki KONDO, Tadayoshi UECHI
  • Publication number: 20160372206
    Abstract: A non-volatile memory device includes a first electrode layer, a second electrode layer adjacent to the first electrode layer, a third electrode layer adjacent to the second electrode layer, a fourth electrode layer adjacent to the third electrode layer, and a channel body extending through the first electrode layer, the second electrode layer, the third electrode layer and the fourth electrode layer in a first direction. The device further includes a circuit electrically connected to the first electrode layer, the second electrode layer, the third electrode layer, the fourth electrode layer, and the channel body. The circuit providing the second electrode layer with a first potential, the third electrode layer with a second potential higher than the first potential, the fourth electrode layer with a third potential between the first potential and the second potential and the channel body with a potential rising in the first direction.
    Type: Application
    Filed: December 15, 2015
    Publication date: December 22, 2016
    Applicant: Kabushiki Kaisha Toshiba
    Inventors: Hikari Tajima, Masaki Kondo, Tsukasa Nakai, Takashi Izumida, Nobutoshi Aoki
  • Patent number: 9502103
    Abstract: A semiconductor memory device according to an embodiment includes: a semiconductor substrate; and a memory cell array which is arranged above the semiconductor substrate in a first direction. The memory cell array includes: a semiconductor layer which extends in the first direction; a first conductive line which extends in a second direction crossing the first direction; a variable resistance film which is arranged at an intersection between the semiconductor layer and the first conductive line; a plurality of second conductive lines which are arranged in the second direction sandwiching the semiconductor layer and extend in the first direction; and a plurality of third conductive lines which are electrically connected to the second conductive lines. Two of the second conductive lines neighboring to each other in the second direction with the semiconductor layer interposed therebetween are electrically connected to different third conductive lines.
    Type: Grant
    Filed: March 14, 2016
    Date of Patent: November 22, 2016
    Assignee: KABUSHIKI KAISHA TOSHIBA
    Inventors: Hiroyoshi Tanimoto, Takashi Izumida
  • Patent number: 9450026
    Abstract: According to an embodiment, a semiconductor device includes at least two control electrodes, a plurality of semiconductor layers and an insulating film. Each control electrode extends in a first direction. The semiconductor layers are provided between the control electrodes, and arranged in the first direction. Each semiconductor layer extends in a second direction orthogonal to the first direction. The insulating film covers side surfaces of the semiconductor layers, and is disposed between the control electrodes. Each semiconductor layer has a side surface that includes at least one curved surface swelling in a direction from a center of the semiconductor layer to the insulating film.
    Type: Grant
    Filed: August 21, 2014
    Date of Patent: September 20, 2016
    Assignee: Kabushiki Kaisha Toshiba
    Inventors: Hikari Tajima, Masaki Kondo, Tsukasa Nakai, Takashi Izumida, Nobuaki Yasutake
  • Patent number: 9379164
    Abstract: An integrated circuit device according to an embodiment includes a semiconductor substrate, a first semiconductor member and a second semiconductor member provided on the semiconductor substrate, a first electrode disposed between the first semiconductor member and the second semiconductor member, and a second electrode disposed between the semiconductor substrate and the first electrode. The first semiconductor member and the second semiconductor member extend in a first direction perpendicular to an upper surface of the semiconductor substrate. The first semiconductor member and the second semiconductor member are separated in a second direction orthogonal to the first direction. The first electrode extends in a third direction intersecting both the first direction and the second direction. The second electrode extends in the third direction.
    Type: Grant
    Filed: February 25, 2015
    Date of Patent: June 28, 2016
    Assignee: KABUSHIKI KAISHA TOSHIBA
    Inventors: Tsukasa Nakai, Masaki Kondo, Hikari Tajima, Hiroki Tokuhira, Takashi Izumida, Takashi Kurusu, Nobutoshi Aoki, Takahisa Kanemura, Tadayoshi Uechi
  • Patent number: 9287499
    Abstract: An integrated circuit device according to an embodiment includes an electrode extending in a first direction, two semiconductor members spaced from each other in the first direction and extending in a second direction crossing the first direction, an insulating film placed between each of the two semiconductor members and the electrode and made of a first insulating material, and a first dielectric member placed between the two semiconductor members and made of a second insulating material having a higher permittivity than the first insulating material.
    Type: Grant
    Filed: August 20, 2014
    Date of Patent: March 15, 2016
    Assignee: Kabushiki Kaisha Toshiba
    Inventors: Hikari Tajima, Masaki Kondo, Tsukasa Nakai, Takashi Izumida, Nobuaki Yasutake
  • Publication number: 20160064452
    Abstract: A memory device according to an embodiment includes a memory element; and a transistor including a semiconductor layer and a plurality of gates, wherein the plurality of gates include: a first set of gates, the gates being disposed in a manner to sandwich the semiconductor layer, and a second set of gates, the gates being disposed in a manner to sandwich the semiconductor layer, the gates included in the first set is disposed in a manner to separate from the gates included in the second set in a direction along a side surface of the semiconductor layer.
    Type: Application
    Filed: January 12, 2015
    Publication date: March 3, 2016
    Applicant: KABUSHIKI KAISHA TOSHIBA
    Inventors: Yoshihiro UEDA, Tsukasa NAKAI, Masaki KONDO, Hikari TAJIMA, Hiroki TOKUHIRA, Takashi IZUMIDA