Patents by Inventor Toshiyuki Oka

Toshiyuki Oka 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: 8809833
    Abstract: Certain embodiments provide a method for manufacturing a semiconductor light emitting device, including: providing a first stack film on a first substrate, the first stack film being formed by stacking a p-type nitride semiconductor layer, an active layer having a multiquantum well structure of a nitride semiconductor, and an n-type nitride semiconductor layer in this order; forming an n-electrode on an upper face of the n-type nitride semiconductor layer; and forming a concave-convex region on the upper face of the n-type nitride semiconductor layer by performing wet etching on the upper face of the n-type nitride semiconductor layer with the use of an alkaline solution, except for a region in which the n-electrode is formed.
    Type: Grant
    Filed: October 18, 2013
    Date of Patent: August 19, 2014
    Assignee: Kabushiki Kaisha Toshiba
    Inventors: Kotaro Zaima, Toru Gotoda, Toshiyuki Oka, Shinya Nunoue
  • Publication number: 20140225061
    Abstract: Certain embodiments provide a semiconductor light emitting device including: a first metal layer; a stack film including a p-type nitride semiconductor layer, an active layer, and an n-type nitride semiconductor layer; an n-electrode; a second metal layer; and a protection film protecting an outer circumferential region of the upper face of the n-type nitride semiconductor layer, side faces of the stack film, a region of an upper face of the second metal layer other than a region in contact with the p-type nitride semiconductor layer, and a region of an upper face of the first metal layer other than a region in contact with the second metal layer. Concavities and convexities are formed in a region of the upper face of the n-type nitride semiconductor layer, the region being outside the region in which the n-electrode is provided and being outside the regions covered with the protection film.
    Type: Application
    Filed: April 15, 2014
    Publication date: August 14, 2014
    Applicant: KABUSHIKI KAISHA TOSHIBA
    Inventors: Kotaro ZAIMA, Toru GOTODA, Toshiyuki OKA, Shinya NUNOUE
  • Publication number: 20140191269
    Abstract: According to one embodiment, a semiconductor light emitting device includes a stacked structure body, a first electrode, a second electrode, and a dielectric body part. The stacked structure body includes a first semiconductor layer, having a first portion and a second portion juxtaposed with the first portion, a light emitting layer provided on the second portion, a second semiconductor layer provided on the light emitting layer. The first electrode includes a contact part provided on the first portion and contacting the first layer. The second electrode includes a first part provided on the second semiconductor layer and contacting the second layer, and a second part electrically connected with the first part and including a portion overlapping with the contact part when viewed from the first layer toward the second layer. The dielectric body part is provided between the contact part and the second part.
    Type: Application
    Filed: March 10, 2014
    Publication date: July 10, 2014
    Applicant: KABUSHIKI KAISHA TOSHIBA
    Inventors: Hiroshi KATSUNO, Satoshi Mitsugi, Toshiyuki Oka, Shinya Nunoue
  • Patent number: 8766305
    Abstract: A semiconductor light emitting device has a light emitting element, a first electrode layer, a second electrode layer, a seed electrode layer and a plated layer. The light emitting element has a nitride-based III-V compound semiconductor on a substrate and a light extraction surface. The first electrode layer is provided on the light extraction surface. The second electrode layer is provided on a surface opposite to the light extraction surface. The seed electrode layer is configured to cover the entire surface of the second electrode layer. The plated layer is provided on the seed electrode layer. The light emitting element has a light emitting layer, first conductive type semiconductor layer, and second conductive type semiconductor layer, and has a forward tapered shape of a width which gradually narrows in order of the second conductive type semiconductor layer, the light emitting layer and the first conductive type semiconductor layer.
    Type: Grant
    Filed: November 30, 2012
    Date of Patent: July 1, 2014
    Assignee: Kabushiki Kaisha Toshiba
    Inventors: Toru Gotoda, Toshiyuki Oka, Shinya Nunoue, Kotaro Zaima
  • Patent number: 8766297
    Abstract: According to one embodiment, a semiconductor light emitting device includes a stacked structural body, first and second electrodes, a high resistance layer and a transparent conductive layer. The stacked structural body includes first and second semiconductor layers and a light emitting layer. The first semiconductor layer is disposed between the first electrode and the second semiconductor layer. The second semiconductor layer is disposed between the second electrode and the first semiconductor layer. The second electrode has reflectivity with respect to luminescent light. The high resistance layer is in contact with the second semiconductor layer between the second semiconductor layer and the second electrode and includes a portion overlapping with the first electrode. The transparent conductive layer is in contact with the second semiconductor layer between the second semiconductor layer and the second electrode.
    Type: Grant
    Filed: February 18, 2011
    Date of Patent: July 1, 2014
    Assignee: Kabushiki Kaisha Toshiba
    Inventors: Toshihide Ito, Toshiyuki Oka, Kotaro Zaima, Taisuke Sato, Shinya Nunoue
  • Patent number: 8735925
    Abstract: Certain embodiments provide a semiconductor light emitting device including: a first metal layer; a stack film including a p-type nitride semiconductor layer, an active layer, and an n-type nitride semiconductor layer; an n-electrode; a second metal layer; and a protection film protecting an outer circumferential region of the upper face of the n-type nitride semiconductor layer, side faces of the stack film, a region of an upper face of the second metal layer other than a region in contact with the p-type nitride semiconductor layer, and a region of an upper face of the first metal layer other than a region in contact with the second metal layer. Concavities and convexities are formed in a region of the upper face of the n-type nitride semiconductor layer, the region being outside the region in which the n-electrode is provided and being outside the regions covered with the protection film.
    Type: Grant
    Filed: April 18, 2012
    Date of Patent: May 27, 2014
    Assignee: Kabushiki Kaisha Toshiba
    Inventors: Kotaro Zaima, Toru Gotoda, Toshiyuki Oka, Shinya Nunoue
  • Patent number: 8680548
    Abstract: A semiconductor light emitting device has a support substrate, a light emitting element, and underfill material. The light emitting element includes a nitride-based group III-V compound semiconductor layer contacted via a bump on the support substrate. The underfill material is disposed between the support substrate and the light emitting element, the underfill material comprising a rib portion disposed outside of an end face of the light emitting element to surround the end surface of the light emitting element.
    Type: Grant
    Filed: September 2, 2010
    Date of Patent: March 25, 2014
    Assignee: Kabushiki Kaisha Toshiba
    Inventors: Toru Gotoda, Hajime Nago, Toshiyuki Oka, Kotaro Zaima, Shinya Nunoue
  • Publication number: 20140077250
    Abstract: According to one embodiment, a semiconductor light emitting device includes first and second conductive layers, a first semiconductor layer of a first conductivity type, a second semiconductor layer of a second conductivity type, and a light emitting part. The second semiconductor layer is provided between the first conductive layer and the first semiconductor layer. The light emitting part is provided between the first and second semiconductor layers. The second conductive layer is in contact with the second semiconductor layer and the first conductive layer between the second semiconductor layer and the first conductive layer. The first and second conductive layers are transmittable to light emitted from the light emitting part. The first conductive layer includes a polycrystal having a first average grain diameter. The second conductive layer includes a polycrystal having a second average grain diameter of 150 nanometers or less and smaller than the first average grain diameter.
    Type: Application
    Filed: November 25, 2013
    Publication date: March 20, 2014
    Applicant: Kabushiki Kaisha Toshiba
    Inventors: Toshihide ITO, Toshiyuki Oka, Shinya Nunoue
  • Publication number: 20140048769
    Abstract: Certain embodiments provide a method for manufacturing a semiconductor light emitting device, including: providing a first stack film on a first substrate, the first stack film being formed by stacking a p-type nitride semiconductor layer, an active layer having a multiquantum well structure of a nitride semiconductor, and an n-type nitride semiconductor layer in this order; forming an n-electrode on an upper face of the n-type nitride semiconductor layer; and forming a concave-convex region on the upper face of the n-type nitride semiconductor layer by performing wet etching on the upper face of the n-type nitride semiconductor layer with the use of an alkaline solution, except for a region in which the n-electrode is formed.
    Type: Application
    Filed: October 18, 2013
    Publication date: February 20, 2014
    Applicant: Kabushiki Kaisha Toshiba
    Inventors: Kotaro ZAIMA, Toru GOTODA, Toshiyuki OKA, Shinya NUNOUE
  • Patent number: 8653498
    Abstract: According to one embodiment, a semiconductor light emitting device includes: a stacked structural body, a first electrode; and a second electrode. The stacked structural body includes a first semiconductor layer of n-type, a second semiconductor layer of p-type, and a light emitting portion provided therebetween. The first electrode includes a first contact electrode portion. The second electrode includes a second contact electrode portion and a p-side pad electrode. A sheet resistance of the second contact electrode portion is lower than a sheet resistance of the first semiconductor layer. The p-side pad electrode is provided farther inward than a circumscribed rectangle of the first contact electrode portion, and the first contact electrode portion is provided farther outward than a circumscribed rectangle of the p-side pad electrode.
    Type: Grant
    Filed: February 23, 2011
    Date of Patent: February 18, 2014
    Assignee: Kabushiki Kaisha Toshiba
    Inventors: Shigeya Kimura, Taisuke Sato, Toshihide Ito, Takahiro Sato, Toshiyuki Oka, Shinya Nunoue
  • Patent number: 8643044
    Abstract: According to one embodiment, a semiconductor light emitting device includes: a stacked structure body, first and second electrodes, and a pad layer. The body includes first semiconductor layer of a first conductivity type, a light emitting layer, and a second semiconductor layer of second conductivity type. The first semiconductor layer has first and second portions. The light emitting layer is provided on the second portion. The second semiconductor layer is provided on the light emitting layer. The first electrode is provided on the first portion. The second electrode is provided on the second semiconductor layer and is transmittable to light emitted from the light emitting layer. The pad layer is connected to the second electrode. A transmittance of the pad layer is lower than that of the second electrode. A sheet resistance of the second electrode increases continuously along a direction from the pad layer toward the first electrode.
    Type: Grant
    Filed: August 31, 2011
    Date of Patent: February 4, 2014
    Assignee: Kabushiki Kaisha Toshiba
    Inventors: Koichi Tachibana, Shigeya Kimura, Toshiki Hikosaka, Taisuke Sato, Toshiyuki Oka, Shinya Nunoue
  • Patent number: 8623683
    Abstract: According to one embodiment, in a nitride semiconductor light emitting device, a first clad layer includes an n-type nitride semiconductor. An active layer is formed on the first clad layer, and includes an In-containing nitride semiconductor. A GaN layer is formed on the active layer. A first AlGaN layer is formed on the GaN layer, and has a first Al composition ratio. A p-type second AlGaN layer is formed on the first AlGaN layer, has a second Al composition ratio higher than the first Al composition ratio, and contains a larger amount of Mg than the GaN layer and the first AlGaN layer. A second clad layer is formed on the second AlGaN layer, and includes a p-type nitride semiconductor.
    Type: Grant
    Filed: January 10, 2013
    Date of Patent: January 7, 2014
    Assignee: Kabushiki Kaisha Toshiba
    Inventors: Hajime Nago, Koichi Tachibana, Toshiyuki Oka, Shigeya Kimura, Shinya Nunoue
  • Patent number: 8623676
    Abstract: According to one embodiment, a semiconductor light emitting device includes first and second conductive layers, a first semiconductor layer of a first conductivity type, a second semiconductor layer of a second conductivity type, and a light emitting part. The second semiconductor layer is provided between the first conductive layer and the first semiconductor layer. The light emitting part is provided between the first and second semiconductor layers. The second conductive layer is in contact with the second semiconductor layer and the first conductive layer between the second semiconductor layer and the first conductive layer. The first and second conductive layers are transmittable to light emitted from the light emitting part. The first conductive layer includes a polycrystal having a first average grain diameter. The second conductive layer includes a polycrystal having a second average grain diameter of 150 nanometers or less and smaller than the first average grain diameter.
    Type: Grant
    Filed: August 26, 2011
    Date of Patent: January 7, 2014
    Assignee: Kabushiki Kaisha Toshiba
    Inventors: Toshihide Ito, Toshiyuki Oka, Shinya Nunoue
  • Patent number: 8564006
    Abstract: According to one embodiment, a nitride semiconductor device includes a substrate and a semiconductor functional layer. The substrate is a single crystal. The semiconductor functional layer is provided on a major surface of the substrate and includes a nitride semiconductor. The substrate includes a plurality of structural bodies disposed in the major surface. Each of the plurality of structural bodies is a protrusion provided on the major surface or a recess provided on the major surface. An absolute value of an angle between a nearest direction of an arrangement of the plurality of structural bodies and a nearest direction of a crystal lattice of the substrate in a plane parallel to the major surface is not less than 1 degree and not more than 10 degrees.
    Type: Grant
    Filed: February 27, 2012
    Date of Patent: October 22, 2013
    Assignee: Kabushiki Kaisha Toshiba
    Inventors: Koichi Tachibana, Hisashi Yoshida, Hiroshi Ono, Hajime Nago, Yoshiyuki Harada, Toshiki Hikosaka, Maki Sugai, Toshiyuki Oka, Shinya Nunoue
  • Publication number: 20130248921
    Abstract: According to one embodiment, a semiconductor light emitting device includes a stacked structural body, a first electrode, and a second electrode. The stacked structural body includes a first semiconductor layer of a first conductivity type, a second semiconductor layer of a second conductivity type, and a light emitting portion. The stacked structural body has a first major surface on a side of the second semiconductor layer. The first electrode is provided on the first semiconductor. The second electrode is provided on the second semiconductor layer. The first electrode includes a first pad portion and a first extending portion that extends from the first pad portion along a first extending direction. The first extending portion includes a first width-increasing portion. A width of the first width-increasing portion along a direction orthogonal to the first extending direction is increased from the first pad portion toward an end of the first extending portion.
    Type: Application
    Filed: May 13, 2013
    Publication date: September 26, 2013
    Applicant: Kabushiki Kaisha Toshiba
    Inventors: Shigeya KIMURA, Taisuke SATO, Toshihide ITO, Toshiyuki OKA, Shinya NUNOUE
  • Publication number: 20130234298
    Abstract: According to an embodiment, a method for manufacturing a semiconductor device includes a placement step and a bonding step. The placement step faces a semiconductor active portion toward a support substrate portion via a bonding portion disposed between the semiconductor active portion and the support substrate portion. The bonding portion includes a bonding layer and a light absorption layer, absorptance of the light absorption layer for laser light being higher than or equal to absorptance of the bonding layer for the laser light. The bonding step bonds the semiconductor active portion and the support substrate portion by irradiating the light absorption layer with the laser light through the support substrate portion and melting the bonding layer by thermal conduction from the light absorption layer heated by the laser light.
    Type: Application
    Filed: August 31, 2012
    Publication date: September 12, 2013
    Applicant: Kabushiki Kaisha Toshiba
    Inventors: Satoshi MITSUGI, Toshiyuki OKA, Shinya NUNOUE, Hiroshi KATSUNO
  • Publication number: 20130228745
    Abstract: According to one embodiment, a nitride semiconductor device includes a first layer and a functional layer. The first layer is formed on an amorphous layer, includes aluminum nitride, and has a compressive strain or a tensile strain. The functional layer is formed on the first layer and includes a nitride semiconductor.
    Type: Application
    Filed: March 15, 2013
    Publication date: September 5, 2013
    Applicant: Kabushiki Kaisha Toshiba
    Inventors: Hiroshi ONO, Tomonari Shioda, Naoharu Sugiyama, Toshiyuki Oka, Shinya Nunoue
  • Patent number: 8470625
    Abstract: A method of fabricating semiconductor light emitting device forms a laminated film by laminating an n-type nitride semiconductor layer, an active layer and a p-type nitride semiconductor layer in order on a uneven main surface of a first substrate, forms a plurality of first electrodes, on an upper surface of the p-type nitride semiconductor layer, forms a first metal layer to cover surfaces of the plurality of first electrodes and the p-type nitride semiconductor layer, forms a second metal layer on an upper surface of the second substrate, joins the first and second metal layers by facing the first and second substrates, cuts the first substrate or forming a groove on the first substrate along a border of the light emitting element from a surface side opposite to the first metal layer on the first substrate, and irradiates a laser toward areas of the light emitting devices from a surface side opposite to the first metal layer on the first substrate to peel off the first substrate.
    Type: Grant
    Filed: March 1, 2011
    Date of Patent: June 25, 2013
    Assignee: Kabushiki Kaisha Toshiba
    Inventors: Kotaro Zaima, Toru Gotoda, Toshiyuki Oka, Shinya Nunoue
  • Publication number: 20130153922
    Abstract: A semiconductor light emitting device has a light emitting element, a first electrode layer, a second electrode layer, a seed electrode layer and a plated layer. The light emitting element has a nitride-based III-V compound semiconductor on a substrate and a light extraction surface. The first electrode layer is provided on the light extraction surface. The second electrode layer is provided on a surface opposite to the light extraction surface. The seed electrode layer is configured to cover the entire surface of the second electrode layer. The plated layer is provided on the seed electrode layer. The light emitting element has a light emitting layer, first conductive type semiconductor layer, and second conductive type semiconductor layer, and has a forward tapered shape of a width which gradually narrows in order of the second conductive type semiconductor layer, the light emitting layer and the first conductive type semiconductor layer.
    Type: Application
    Filed: November 30, 2012
    Publication date: June 20, 2013
    Inventors: Toru Gotoda, Toshiyuki Oka, Shinya Nunoue, Kotaro Zaima
  • Patent number: 8461611
    Abstract: According to one embodiment, a semiconductor light emitting device includes a first semiconductor layer, a second semiconductor layer and a light emitting part. The first semiconductor layer includes an n-type semiconductor layer. The second semiconductor layer includes a p-type semiconductor layer. The light emitting part is provided between the first semiconductor layer and the second semiconductor layer, and includes a plurality of barrier layers and a well layer provided between the plurality of barrier layers. The first semiconductor layer has a first irregularity and a second irregularity. The first irregularity is provided on a first major surface of the first semiconductor layer on an opposite side to the light emitting part. The second irregularity is provided on a bottom face and a top face of the first irregularity, and has a level difference smaller than a level difference between the bottom face and the top face.
    Type: Grant
    Filed: August 12, 2011
    Date of Patent: June 11, 2013
    Assignee: Kabushiki Kaisha Toshiba
    Inventors: Hiroshi Ono, Toshiki Hikosaka, Tomoko Morioka, Toshiyuki Oka, Shinya Nunoue