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: 8178891
    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: September 2, 2010
    Date of Patent: May 15, 2012
    Assignee: Kabushiki Kaisha Toshiba
    Inventors: Kotaro Zaima, Toru Gotoda, Toshiyuki Oka, Shinya Nunoue
  • Patent number: 8148890
    Abstract: A light-emitting device includes a support substrate which includes a light-emitting layer and a light extraction surface, and a light transmission layer, formed on the light extraction surface of the support substrate, having a periodic refractive index distribution structure in an in-plane direction and a thickness direction, the light transmission layer including a plurality of projections formed of a having a refractive index lower than that of the support substrate.
    Type: Grant
    Filed: August 21, 2008
    Date of Patent: April 3, 2012
    Assignee: Kabushiki Kaisha Toshiba
    Inventors: Saori Abe, Toshiyuki Oka, Shinya Nunoue
  • Publication number: 20120061713
    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: Application
    Filed: August 31, 2011
    Publication date: March 15, 2012
    Applicant: Kabushiki Kaisha Toshiba
    Inventors: Koichi Tachibana, Shigeya Kimura, Toshiki Hikosaka, Taisuke Sato, Toshiyuki Oka, Shinya Nunoue
  • Publication number: 20120056220
    Abstract: According to one embodiment, in a light emitting device, a substrate is transparent to a wavelength of emitted light. A first dielectric layer is formed in a first region on the substrate, and has a refractive index smaller than a refractive index of the substrate. A second dielectric layer is formed in a second region on the substrate surrounding the first region, and has a refractive index larger than the refractive index of the substrate. A first semiconductor layer is formed on the first dielectric layer, the second dielectric layer and the substrate. A second semiconductor layer is formed on the first semiconductor layer, and includes an active layer having a PN junction.
    Type: Application
    Filed: September 6, 2011
    Publication date: March 8, 2012
    Applicant: Kabushiki Kaisha Toshiba
    Inventors: Taisuke SATO, Masanobu Ando, Hajime Nago, Koichi Tachibana, Toshiyuki Oka, Shinya Nunoue
  • Publication number: 20120056154
    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: Application
    Filed: March 1, 2011
    Publication date: March 8, 2012
    Applicant: Kabushiki Kaisha Toshiba
    Inventors: Kotaro ZAIMA, Toru Gotoda, Toshiyuki Oka, Shinya Nunoue
  • Publication number: 20120049157
    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: Application
    Filed: August 30, 2011
    Publication date: March 1, 2012
    Inventors: Hajime NAGO, Koichi Tachibana, Toshiyuki Oka, Shigeya Kimura, Shinya Nunoue
  • Publication number: 20120043550
    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: Application
    Filed: February 18, 2011
    Publication date: February 23, 2012
    Applicant: KABUSHIKI KAISHA TOSHIBA
    Inventors: Toshihide ITO, Toshiyuki Oka, Kotaro Zaima, Taisuke Sato, Shinya Nunoue
  • Publication number: 20120032213
    Abstract: According to one embodiment, a semiconductor light emitting device includes a stacked structural body, a first, a second and a third conductive layer. The stacked structural body includes first and second semiconductors and a light emitting layer provided therebetween. The second semiconductor layer is disposed between the first conductive layer and the light emitting layer. The first conductive layer is transparent. The first conductive layer has a first major surface on a side opposite to the second semiconductor layer. The second conductive layer is in contact with the first major surface. The third conductive layer is in contact with the first major surface and has a reflectance higher than a reflectance of the second conductive layer. The third conductive layer includes an extending part extending in parallel to the first major surface. At least a portion of the extending part is not covered by the second conductive layer.
    Type: Application
    Filed: February 17, 2011
    Publication date: February 9, 2012
    Applicant: KABUSHIKI KAISHA TOSHIBA
    Inventors: Taisuke SATO, Toshiyuki Oka, Koichi Tachibana, Shinya Nunoue
  • Publication number: 20120032214
    Abstract: According to one embodiment, a semiconductor light emitting device includes a first semiconductor layer of a first conductivity type, a second semiconductor layer of a second conductivity type, a light emitting portion, a first transparent conductive layer, and a second transparent conductive layer. The light emitting portion is provided between the first and second semiconductor layers. The second semiconductor layer is disposed between the first transparent conductive layer and the light emitting portion. The first transparent conductive layer includes oxygen. The second transparent conductive layer is provided between the second semiconductor layer and the first transparent conductive layer. The second transparent conductive layer has a refractive index higher than a refractive index of the first transparent conductive layer, and includes oxygen at a concentration higher than a concentration of oxygen included in the first transparent conductive layer.
    Type: Application
    Filed: February 18, 2011
    Publication date: February 9, 2012
    Applicant: KABUSHIKI KAISHA TOSHIBA
    Inventors: Toshihide Ito, Taisuke Sato, Toshiyuki Oka, Shinya Nunoue
  • Publication number: 20120032139
    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: Application
    Filed: February 23, 2011
    Publication date: February 9, 2012
    Applicant: KABUSHIKI KAISHA TOSHIBA
    Inventors: Shigeya KIMURA, Taisuke Sato, Toshihide Ito, Takahiro Sato, Toshiyuki Oka, Shinya Nunoue
  • Publication number: 20110284908
    Abstract: According to one embodiment, a semiconductor light emitting device includes a stacked structural body, a first electrode, a second electrode, a third electrode, and a fourth electrode. The stacked structural body includes a first semiconductor layer, a second semiconductor layer, and a light emitting layer provided between the first semiconductor layer and the second semiconductor layer. The first electrode is electrically connected to the first semiconductor layer. The second electrode forms an ohmic contact with the second semiconductor layer. The second electrode is translucent to light emitted from the light emitting layer. The third electrode penetrates through the second electrode and is electrically connected to the second electrode to form Shottky contact with the second semiconductor layer. The third electrode is disposed between the fourth electrode and the second semiconductor layer.
    Type: Application
    Filed: August 2, 2011
    Publication date: November 24, 2011
    Applicant: KABUSHIKI KAISHA TOSHIBA
    Inventors: Eiji MURAMOTO, Shinya NUNOUE, Toshiyuki OKA
  • Publication number: 20110220933
    Abstract: A semiconductor light emitting device has a light emitting element, and first and second electrodes. The light emitting element has a nitride-based III-V compound semiconductor on a substrate. The first and second electrodes are disposed on both sides of the light emitting element, respectively. The light emitting element has a light emitting layer, a first conductive type semiconductor layer, and a second conductive type semiconductor layer. The first conductive type semiconductor layer is disposed between the light emitting layer and the first electrode. The second conductive type semiconductor layer is disposed between the light emitting layer and the second electrode. One surface of the first conductive type semiconductor layer contacts the first electrode and is a light extraction surface which is roughly processed so as to have two or more kinds of oblique angles.
    Type: Application
    Filed: September 2, 2010
    Publication date: September 15, 2011
    Applicant: Kabushiki Kaisha Toshiba
    Inventors: Toru GOTODA, Takahiro Sato, Toshiyuki Oka, Shinya Nunoue, Kotaro Zaima
  • Publication number: 20110220935
    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. The light emitting element having a light extraction surface. The first electrode layer on the light extraction surface. The second electrode layer is provided on a surface opposite to the light extraction surface of the light emitting element. 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, a first conductive type semiconductor layer, and a second conductive type semiconductor layer.
    Type: Application
    Filed: September 2, 2010
    Publication date: September 15, 2011
    Applicant: Kabushiki Kaisha Toshiba
    Inventors: Toru GOTODA, Toshiyuki Oka, Shinya Nunoue, Kotaro Zaima
  • Publication number: 20110220934
    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: Application
    Filed: September 2, 2010
    Publication date: September 15, 2011
    Applicant: Kabushiki Kaisha Toshiba
    Inventors: Toru Gotoda, Hajime Nago, Toshiyuki Oka, Kotaro Zaima, Shinya Nunoue
  • Publication number: 20110215293
    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: September 2, 2010
    Publication date: September 8, 2011
    Applicant: Kabushiki Kaisha Toshiba
    Inventors: Kotaro Zaima, Toru Gotoda, Toshiyuki Oka, Shinya Nunoue
  • Publication number: 20110215370
    Abstract: According to one embodiment, a semiconductor light-emitting device having high light extraction efficiency is provided. The semiconductor light-emitting device includes a light transmissive substrate; a nitride semiconductor layer of a first conduction type formed on or above a top face side of the light transmissive substrate; an active layer made of nitride semiconductor formed on a top face of the nitride semiconductor layer of the first conduction type; a nitride semiconductor layer of a second conduction type formed on a top face of the active layer; a dielectric layer formed on a bottom face of the light transmissive substrate and having a refractive index lower than that of the light transmissive substrate; and a metal layer formed on a bottom face of the dielectric layer. And an interface between the light transmissive substrate and the dielectric layer is a uneven face, and an interface between the dielectric layer and the metal layer is a flat face.
    Type: Application
    Filed: September 1, 2010
    Publication date: September 8, 2011
    Applicant: Kabushiki Kaisha Toshiba
    Inventors: Taisuke Sato, Toshiyuki Oka, Koichi Tachibana, Shinya Nunoue, Kazufumi Shiozawa, Takayoshi Fujii
  • Publication number: 20110215351
    Abstract: According to one embodiment, a semiconductor light-emitting device includes an n-type semiconductor layer including a nitride semiconductor, a p-type semiconductor layer including a nitride semiconductor, a light-emitting portion and a stacked body. The light-emitting portion is provided between the n-type and p-type semiconductor layers and includes a barrier layer and a well layer. The well layer is stacked with the barrier layer. The stacked body is provided between the light-emitting portion and the n-type semiconductor layer and includes a first layer and a second layer. The second layer is stacked with the first layer. Average In composition ratio of the stacked body is higher than 0.4 times average In composition ratio of the light-emitting portion. The layer thickness tb of the barrier layer is 10 nanometers or less.
    Type: Application
    Filed: September 3, 2010
    Publication date: September 8, 2011
    Applicant: Kabushiki Kaisha Toshiba
    Inventors: Shigeya Kimura, Hajime Nago, Toshiyuki Oka, Koichi Tachibana, Toshiki Hikosaka, Shinya Nunoue
  • Publication number: 20110215363
    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: September 3, 2010
    Publication date: September 8, 2011
    Applicant: Kabushiki Kaisha Toshiba
    Inventors: Shigeya Kimura, Taisuke Sato, Toshihide Ito, Toshiyuki Oka, Shinya Nunoue
  • Publication number: 20110215292
    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: September 2, 2010
    Publication date: September 8, 2011
    Applicant: Kabushiki Kaisha Toshiba
    Inventors: Kotaro Zaima, Toru Gotoda, Toshiyuki Oka, Shinya Nunoue
  • Patent number: 8004004
    Abstract: The present invention provides a semiconductor light emitting element with excellent color rendering properties, a method for manufacturing the semiconductor light emitting element, and a light emitting device. The semiconductor light emitting element includes: a semiconductor substrate that has a convex portion having a tilted surface as an upper face, and a concave portion formed on either side of the convex portion, the concave portion having a smaller width than the convex portion, a bottom face of the concave portion being located in a deeper position than the upper face of the convex portion; and a light emitting layer that is made of a nitride-based semiconductor and is formed on the semiconductor substrate so as to cover at least the convex portion.
    Type: Grant
    Filed: November 29, 2010
    Date of Patent: August 23, 2011
    Assignee: Kabushiki Kaisha Toshiba
    Inventors: Hajime Nago, Koichi Tachibana, Kotaro Zaima, Shinji Saito, Shinya Nunoue, Toshiyuki Oka