Patents by Inventor Ryuji Ohba

Ryuji Ohba 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: 10903228
    Abstract: A semiconductor storage device includes a semiconductor substrate and a plurality of first wiring layers stacked above the semiconductor substrate in a first direction orthogonal to the semiconductor substrate, and extending in a second direction intersecting the first direction and parallel to the semiconductor substrate. The device further includes a first memory pillar including a semiconductor layer and a first insulation layer extending in the first direction, the first insulation layer provided between the plurality of first wiring layers and the semiconductor layer so as to contact the semiconductor layer, and charge storage layers provided respectively between the plurality of first wiring layers and the first insulation layer. One or more of the charge storage layers is in contact with the first insulation layer. A plurality of second insulation layers is provided between each of the plurality of first wiring layers and each of the charge storage layers.
    Type: Grant
    Filed: August 27, 2018
    Date of Patent: January 26, 2021
    Assignee: TOSHIBA MEMORY CORPORATION
    Inventors: Hiroki Sasaki, Atsushi Murakoshi, Ryuji Ohba
  • Patent number: 10658480
    Abstract: A memory device includes plural electrode layers stacked in a first direction, a semiconductor layer interacting with the plural electrode layers and extending in the first direction, a first insulating film provided between the semiconductor layer and at least one electrode layer and extending along the semiconductor layer in the first direction, and a charge trapping film provided between the electrode layer and the first insulating film. The memory device further includes a second insulating film provided between the charge trapping film and the first insulating film and in contact with the first insulating film. In a flat band state, the charge trapping film has a first trap level located at a level deeper than a conduction band of the semiconductor layer and the second insulating film has a second trap level that is closer to the conduction band of the semiconductor layer than the first trap level.
    Type: Grant
    Filed: September 6, 2018
    Date of Patent: May 19, 2020
    Assignee: TOSHIBA MEMORY CORPORATION
    Inventor: Ryuji Ohba
  • Publication number: 20190296118
    Abstract: A memory device includes plural electrode layers stacked in a first direction, a semiconductor layer interacting with the plural electrode layers and extending in the first direction, a first insulating film provided between the semiconductor layer and at least one electrode layer and extending along the semiconductor layer in the first direction, and a charge trapping film provided between the electrode layer and the first insulating film. The memory device further includes a second insulating film provided between the charge trapping film and the first insulating film and in contact with the first insulating film. In a flat band state, the charge trapping film has a first trap level located at a level deeper than a conduction band of the semiconductor layer and the second insulating film has a second trap level that is closer to the conduction band of the semiconductor layer than the first trap level.
    Type: Application
    Filed: September 6, 2018
    Publication date: September 26, 2019
    Applicant: TOSHIBA MEMORY CORPORATION
    Inventor: Ryuji OHBA
  • Publication number: 20190273092
    Abstract: A semiconductor storage device includes a semiconductor substrate and a plurality of first wiring layers stacked above the semiconductor substrate in a first direction orthogonal to the semiconductor substrate, and extending in a second direction intersecting the first direction and parallel to the semiconductor substrate. The device further includes a first memory pillar including a semiconductor layer and a first insulation layer extending in the first direction, the first insulation layer provided between the plurality of first wiring layers and the semiconductor layer so as to contact the semiconductor layer, and charge storage layers provided respectively between the plurality of first wiring layers and the first insulation layer. One or more of the charge storage layers is in contact with the first insulation layer. A plurality of second insulation layers is provided between each of the plurality of first wiring layers and each of the charge storage layers.
    Type: Application
    Filed: August 27, 2018
    Publication date: September 5, 2019
    Applicant: TOSHIBA MEMORY CORPORATION
    Inventors: Hiroki SASAKI, Atsushi MURAKOSHI, Ryuji OHBA
  • Patent number: 9721654
    Abstract: A memory device according to one embodiment includes a first interconnection, a second interconnection, a charge storage portion provided between the first interconnection and the second interconnection, a tunnel film provided between the first interconnection and the charge storage portion, and a block film. the charge storage portion is capable of accumulating an electron. The tunnel film includes a fine particulate layer that including conductive fine particulates satisfying the Coulomb blockade condition, a first tunnel insulating layer provided between the first interconnection and the fine particulate layer, and a second tunnel insulating layer provided between the fine particulate layer and the charge storage portion. The block film is provided between the charge storage portion and the second interconnection. The block film has an energy structure in which no concave portion with an energy barrier lower than energy barriers on both sides thereof is present.
    Type: Grant
    Filed: September 16, 2016
    Date of Patent: August 1, 2017
    Assignee: KABUSHIKI KAISHA TOSHIBA
    Inventor: Ryuji Ohba
  • Publication number: 20170077111
    Abstract: A semiconductor memory device according to an embodiment includes a plurality of channel layers, a gate-insulating film disposed on the channel layer, a floating gate electrode disposed on the gate-insulating film, a block insulating film disposed over the floating gate electrode, the block insulating film including at least a first insulating film and a second insulating film, the second insulating film including lanthanum and aluminum, and a control gate electrode disposed on the block insulating film. The second insulating film includes an upwardly convex curved portion in a region between the channel layers.
    Type: Application
    Filed: February 16, 2016
    Publication date: March 16, 2017
    Applicant: KABUSHIKI KAISHA TOSHIBA
    Inventor: Ryuji OHBA
  • Publication number: 20160260815
    Abstract: A non-volatile semiconductor memory device has a plurality of semiconductor areas that are arranged at intervals in a first direction on a semiconductor substrate and extend in a second direction crossing the first direction, a gate insulating layer that is arranged on the semiconductor areas, a charge accumulation layer that is arranged on the gate insulating layer and repeats one time or more a width change where a width of the first direction decreases monotonously, increases thereafter, and decreases again, upward from the gate insulating layer, an inter-electrode insulating layer that is arranged on the charge accumulation layer and covers at least a part of a surface of the charge accumulation layer, and a control electrode that is arranged on the inter-electrode insulating layer.
    Type: Application
    Filed: September 8, 2015
    Publication date: September 8, 2016
    Applicant: KABUSHIKI KAISHA TOSHIBA
    Inventor: Ryuji OHBA
  • Publication number: 20160071853
    Abstract: A semiconductor memory device includes a semiconductor substrate, a plurality of element regions that extend in a first direction on an upper surface of the semiconductor substrate, and are arranged in parallel along a second direction crossing the first direction, an element isolation region that is disposed between the element regions, and a charge storage layer and a control gate that are disposed in each of the element regions, each of the charge storage layers having a portion whose width decreases with increasing distance away from the element region. A first insulating film is independently disposed on each of the charge storage layers, and second and third insulating films are disposed over each of the first insulating films.
    Type: Application
    Filed: February 27, 2015
    Publication date: March 10, 2016
    Inventor: Ryuji OHBA
  • Publication number: 20150263121
    Abstract: A semiconductor device including semiconductor substrate having an active region and an element isolation region, the active region isolated by the element isolation region, the element isolation region provided with an element isolation trench; a memory-cell transistor formed above the semiconductor substrate and having a gate electrode formed above the active region via a first insulating film, the gate electrode formed of a stack including a floating gate electrode, a first interelectrode insulating film, and a control gate electrode; an element isolation insulating film filled in the element isolation trench; and a second interelectrode insulating film disposed above the element isolation insulating film so as to form a stack of the second interelectrode insulating film and the control electrode above the element isolation insulating and a dielectric constant of the second interelectrode insulating film being higher than a dielectric constant of the first interelectrode insulating film.
    Type: Application
    Filed: September 11, 2014
    Publication date: September 17, 2015
    Applicant: KABUSHIKI KAISHA TOSHIBA
    Inventors: Kana HIRAYAMA, Ryuji Ohba, Takeshi Kamigaichi
  • Patent number: 9061898
    Abstract: According to one embodiment, a memory device includes the following structure. A first double tunnel junction structure includes a first nanocrystal layer that includes first conductive minute particles, and first and second tunnel insulating films arranged to sandwich the first nanocrystal layer. A second double tunnel junction structure includes a second nanocrystal layer that includes second conductive minute particles, and third and fourth tunnel insulating films arranged to sandwich the second nanocrystal layer. A charge storage layer is arranged between the first and second double tunnel junction structures. First and second conductive layers are arranged to sandwich the first double tunnel junction structure, the charge storage layer, and the second double tunnel junction structure. The first conductive minute particles has an average grain size which is different from that of the second conductive minute particles.
    Type: Grant
    Filed: March 22, 2012
    Date of Patent: June 23, 2015
    Assignee: KABUSHIKI KAISHA TOSHIBA
    Inventor: Ryuji Ohba
  • Patent number: 9041091
    Abstract: According to one embodiment, a device includes a fin type active area on a semiconductor substrate, the active area having an upper surface with a taper shape, having a width in a first direction, and extending in a second direction intersect with the first direction, a first insulating layer on the active area, a charge storage layer on the first insulating layer, the charge storage layer having an upper surface with a taper shape, a second insulating layer covering the upper surface of the charge storage layer, and a control gate electrode on the second insulating layer, the control gate electrode extending in the first direction.
    Type: Grant
    Filed: August 2, 2013
    Date of Patent: May 26, 2015
    Assignee: KABUSHIKI KAISHA TOSHIBA
    Inventor: Ryuji Ohba
  • Patent number: 8969843
    Abstract: According to one embodiment, a memory device includes first and second conductive layers, a variable resistance portion, and a multiple tunnel junction portion. The variable resistance portion is provided between the first and second conductive layers. The multiple tunnel junction portion is provided between the first conductive layer and the variable resistance portion, and includes first, second, and third tunnel insulating films, and first and second nanocrystal layers. The first nanocrystal layer between the first and second tunnel insulating films includes first conductive minute particles. The second nanocrystal layer between the second and third tunnel insulating films includes second conductive minute particles.
    Type: Grant
    Filed: May 29, 2013
    Date of Patent: March 3, 2015
    Assignee: Kabushiki Kaisha Toshiba
    Inventor: Ryuji Ohba
  • Publication number: 20150021678
    Abstract: According to one embodiment, a nonvolatile semiconductor memory device includes a first memory cell on the first fin-type active area, and a second memory cell on the second fin-type active area. Each of widths of charge storage layers of the first and second memory cells becomes narrower upward from below. Each of inter-electrode insulating layers of the first and second memory cells has a contact portion through which both are in contact with each other.
    Type: Application
    Filed: October 10, 2014
    Publication date: January 22, 2015
    Applicant: KABUSHIKI KAISHA TOSHIBA
    Inventor: Ryuji OHBA
  • Patent number: 8916923
    Abstract: According to one embodiment, in a nonvolatile semiconductor memory in which a charge store layer is formed on a tunnel insulating film formed on a channel region of a semiconductor substrate, a first nanoparticle layer containing first conductive nanoparticles is formed on the channel side, and a second nanoparticle layer containing a plurality of second conductive nanoparticles having an average particle size larger than the first conductive nanoparticles is formed on the charge store layer side. An average energy value ?E1 required for charging one electron in the first conductive nanoparticle is smaller than an average energy value ?E required for charging one electron in the second conductive nanoparticle, and a difference between ?E1 and ?E is larger than a heat fluctuation energy (kBT).
    Type: Grant
    Filed: September 2, 2011
    Date of Patent: December 23, 2014
    Assignee: Kabushiki Kaisha Toshiba
    Inventor: Ryuji Ohba
  • Patent number: 8890231
    Abstract: According to one embodiment, a nonvolatile semiconductor memory device includes a first memory cell on the first fin-type active area, and a second memory cell on the second fin-type active area. Each of widths of charge storage layers of the first and second memory cells becomes narrower upward from below. Each of inter-electrode insulating layers of the first and second memory cells has a contact portion through which both are in contact with each other.
    Type: Grant
    Filed: September 5, 2012
    Date of Patent: November 18, 2014
    Assignee: Kabushiki Kaisha Toshiba
    Inventor: Ryuji Ohba
  • Publication number: 20140284679
    Abstract: According to one embodiment, a device includes a fin type active area on a semiconductor substrate, the active area having an upper surface with a taper shape, having a width in a first direction, and extending in a second direction intersect with the first direction, a first insulating layer on the active area, a charge storage layer on the first insulating layer, the charge storage layer having an upper surface with a taper shape, a second insulating layer covering the upper surface of the charge storage layer, and a control gate electrode on the second insulating layer, the control gate electrode extending in the first direction.
    Type: Application
    Filed: August 2, 2013
    Publication date: September 25, 2014
    Applicant: Kabushiki Kaisha Toshiba
    Inventor: Ryuji OHBA
  • Publication number: 20140231740
    Abstract: According to one embodiment, a memory device includes first and second conductive layers, a variable resistance portion, and a multiple tunnel junction portion. The variable resistance portion is provided between the first and second conductive layers. The multiple tunnel junction portion is provided between the first conductive layer and the variable resistance portion, and includes first, second, and third tunnel insulating films, and first and second nanocrystal layers. The first nanocrystal layer between the first and second tunnel insulating films includes first conductive minute particles. The second nanocrystal layer between the second and third tunnel insulating films includes second conductive minute particles.
    Type: Application
    Filed: May 29, 2013
    Publication date: August 21, 2014
    Applicant: Kabushiki Kaisha Toshiba
    Inventor: Ryuji Ohba
  • Patent number: 8742489
    Abstract: According to one embodiment, a nonvolatile semiconductor memory including a first gate insulating film formed on a channel region of a semiconductor substrate, a first particle layer formed in the first gate insulating film, a charge storage part formed on the first gate insulating film, a second gate insulating film which is formed on the charge storage part, a second particle layer formed in the second gate insulating film, and a gate electrode formed on the second gate insulating film. The first particle layer includes first conductive particles that satisfy Coulomb blockade conditions. The second particle layer includes second conductive particles that satisfy Coulomb blockade conditions and differs from the first conductive particles in average particle diameter.
    Type: Grant
    Filed: March 22, 2012
    Date of Patent: June 3, 2014
    Assignee: Kabushiki Kaisha Toshiba
    Inventors: Ryuji Ohba, Daisuke Matsushita
  • Patent number: 8587050
    Abstract: In one embodiment, there is provided a semiconductor memory that includes: a semiconductor substrate having a channel region; a first tunnel insulating film on the channel region; a first fine particle layer on the first tunnel insulating film, the first fine particle layer including first conductive fine particles; a second tunnel insulating film on the first fine particle layer; a second fine particle layer on the second tunnel insulating film, the second fine particle layer including second conductive fine particles; a third tunnel insulating film on the second fine particle layer; a third fine particle layer on the third tunnel insulating film, the third fine particle layer including third conductive fine particles. A mean particle diameter of the second conductive fine particles is larger than that of the first conductive fine particles and that of the third conductive fine particles.
    Type: Grant
    Filed: March 14, 2012
    Date of Patent: November 19, 2013
    Assignee: Kabushiki Kaisha Toshiba
    Inventor: Ryuji Ohba
  • Patent number: RE44630
    Abstract: A semiconductor device includes a semiconductor substrate, and a nonvolatile memory cell provided on the semiconductor substrate, the nonvolatile memory cell including a tunnel insulating film provided on a surface of the semiconductor substrate, the tunnel insulating film including semiconductor grains, the semiconductor grains included in both end portions of the tunnel insulating film having smaller grain size than the semiconductor grains included in other portions of the tunnel insulating film, a charge storage layer provided on the tunnel insulating film, an insulating film provided on the charge storage layer, and a control gate electrode provided on the insulating film.
    Type: Grant
    Filed: September 14, 2012
    Date of Patent: December 10, 2013
    Assignee: Kabushiki Kaisha Toshiba
    Inventors: Tetsuya Kai, Ryuji Ohba, Yoshio Ozawa