Patents by Inventor Toshiki Hikosaka

Toshiki Hikosaka 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: 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: 8637890
    Abstract: According to one embodiment, a light emitting device includes a semiconductor light emitting element, a mounting member, a first wavelength conversion layer, and a first transparent layer. The semiconductor light emitting element emits a first light. The semiconductor light emitting element is placed on the mounting member. The first wavelength conversion layer is provided between the semiconductor light emitting element and the mounting member in contact with the mounting member. The first wavelength conversion layer absorbs the first light and emits a second light having a wavelength longer than a wavelength of the first light. The first transparent layer is provided between the semiconductor light emitting element and the first wavelength conversion layer in contact with the semiconductor light emitting element and the first wavelength conversion layer. The first transparent layer is transparent to the first light and the second light.
    Type: Grant
    Filed: February 6, 2013
    Date of Patent: January 28, 2014
    Assignee: Kabushiki Kaisha Toshiba
    Inventors: Toshiki Hikosaka, Takahiro Sato, Iwao Mitsuishi, Shinya Nunoue
  • Patent number: 8610106
    Abstract: According to one embodiment, a semiconductor light emitting device includes an n-type semiconductor layer, a p-type semiconductor layer and a light emitting part. The light emitting part is provided between the n-type semiconductor layer and the p-type semiconductor layer and includes a first light emitting layer. The first light emitting layer includes a first barrier layer, a first well layer, a first n-side intermediate layer and a first p-side intermediate layer. The barrier layer, the well layer, the n-side layer and the p-side intermediate layer include a nitride semiconductor. An In composition ratio in the n-side layer decreases along a first direction from the n-type layer toward the p-type layer. An In composition ratio in the p-side layer decreases along the first direction. An average change rate of the In ratio in the p-side layer is lower than an average change rate of the In ratio in the n-side layer.
    Type: Grant
    Filed: August 19, 2011
    Date of Patent: December 17, 2013
    Assignee: Kabushiki Kaisha Toshiba
    Inventors: Tomonari Shioda, Toshiki Hikosaka, Yoshiyuki Harada, Naoharu Sugiyama, Shinya Nunoue
  • Patent number: 8598605
    Abstract: According to one embodiment, a semiconductor light-emitting device includes: a first conductivity type first semiconductor layer containing a nitride semiconductor crystal and having a tensile stress in a (0001) surface; a second conductivity type second semiconductor layer containing a nitride semiconductor crystal and having a tensile stress in the (0001) surface; a light emitting layer provided between the first semiconductor layer and the second semiconductor layer, containing a nitride semiconductor crystal, and having an average lattice constant larger than the lattice constant of the first semiconductor layer; and a first stress application layer provided on a side opposite to the light emitting layer of the first semiconductor layer and applying a compressive stress to the first semiconductor layer.
    Type: Grant
    Filed: August 31, 2012
    Date of Patent: December 3, 2013
    Assignee: Kabushiki Kaisha Toshiba
    Inventors: Naoharu Sugiyama, Taisuke Sato, Kotaro Zaima, Jumpei Tajima, Toshiki Hikosaka, Yoshiyuki Harada, Hisashi Yoshida, Shinya Nunoue
  • Patent number: 8592850
    Abstract: According to one embodiment, a light emitting device includes a semiconductor light emitting element to emit a first light, a mounting member, first and second wavelength conversion layers and a transparent layer. The first wavelength conversion layer is provided between the element and the mounting member in contact with the mounting member. The first wavelength conversion layer absorbs the first light and emits a second light having a wavelength longer than a wavelength of the first light. The semiconductor light emitting element is disposed between the second wavelength conversion layer and the first wavelength conversion layer. The second wavelength conversion layer absorbs the first light and emits a third light having a wavelength longer than the wavelength of the first light. The transparent layer is provided between the element and the second wavelength conversion layer. The transparent layer is transparent to the first, second, and third lights.
    Type: Grant
    Filed: November 15, 2012
    Date of Patent: November 26, 2013
    Assignee: Kabushiki Kaisha Toshiba
    Inventors: Toshiki Hikosaka, Takahiro Sato, Iwao Mitsuishi, Shinya Nunoue
  • Publication number: 20130309796
    Abstract: According to one embodiment, a semiconductor light emitting device includes an n-type semiconductor layer, a p-type semiconductor layer, and a light emitting part provided therebetween. The light emitting part includes a plurality of light emitting layers. Each of the light emitting layers includes a well layer region and a non-well layer region which is juxtaposed with the well layer region in a plane perpendicular to a first direction from the n-type semiconductor layer towards the p-type semiconductor layer. Each of the well layer regions has a common An In composition ratio. Each of the well layer regions includes a portion having a width in a direction perpendicular to the first direction of 50 nanometers or more.
    Type: Application
    Filed: July 25, 2013
    Publication date: November 21, 2013
    Applicant: Kabushiki Kaisha Toshiba
    Inventors: Yoshiyuki Harada, Toshiki Hikosaka, Tomonari Shioda, Koichi Tachibana, Hajime Nago, Shinya Nunoue
  • Publication number: 20130292644
    Abstract: According to one embodiment, a semiconductor light emitting device includes an n-type semiconductor layer, a p-type semiconductor layer, a light emitting portion, a first layer, a second layer, and an intermediate layer. The semiconductor layers include nitride semiconductor. The light emitting portion is provided between the n-type semiconductor layer and the p-type semiconductor layer and includes a quantum well layer. The first layer is provided between the light emitting portion and the p-type semiconductor layer and includes AlX1Ga1-x1N having first Al composition ratio x1. The second layer is provided between the first layer and the p-type semiconductor layer and includes Alx2Ga1-x2N having second Al composition ratio x2 higher than the first Al composition ratio x1. The intermediate layer is provided between the first layer and the light emitting portion and has a thickness not smaller than 3 nanometers and not larger than 8 nanometers and includes Inz1Ga1-z1N (0?z1<1).
    Type: Application
    Filed: July 3, 2013
    Publication date: November 7, 2013
    Inventors: Koichi TACHIBANA, Hajime Nago, Toshiki Hikosaka, Shigeya Kimura, 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: 20130237036
    Abstract: According to one embodiment, a method for manufacturing a nitride semiconductor layer is disclosed. The method can include forming a first lower layer on a major surface of a substrate and forming a first upper layer on the first lower layer. The first lower layer has a first lattice spacing along a first axis parallel to the major surface. The first upper layer has a second lattice spacing along the first axis larger than the first lattice spacing. At least a part of the first upper layer has compressive strain. A ratio of a difference between the first and second lattice spacing to the first lattice spacing is not less than 0.005 and not more than 0.019. A growth rate of the first upper layer in a direction parallel to the major surface is larger than that in a direction perpendicular to the major surface.
    Type: Application
    Filed: September 5, 2012
    Publication date: September 12, 2013
    Applicant: Kabushiki Kaisha Toshiba
    Inventors: Toshiki HIKOSAKA, Yoshiyuki HARADA, Hisashi YOSHIDA, Naoharu SUGIYAMA, Shinya NUNOUE
  • Publication number: 20130234106
    Abstract: According to one embodiment, a semiconductor light-emitting device includes: a first conductivity type first semiconductor layer containing a nitride semiconductor crystal and having a tensile stress in a (0001) surface; a second conductivity type second semiconductor layer containing a nitride semiconductor crystal and having a tensile stress in the (0001) surface; a light emitting layer provided between the first semiconductor layer and the second semiconductor layer, containing a nitride semiconductor crystal, and having an average lattice constant larger than the lattice constant of the first semiconductor layer; and a first stress application layer provided on a side opposite to the light emitting layer of the first semiconductor layer and applying a compressive stress to the first semiconductor layer.
    Type: Application
    Filed: August 31, 2012
    Publication date: September 12, 2013
    Applicant: Kabushiki Kaisha Toshiba
    Inventors: Naoharu Sugiyama, Taisuke Sato, Kotaro Zaima, Jumpei Tajima, Toshiki Hikosaka, Yoshiyuki Harada, Hisashi Yoshida, Shinya Nunoue
  • Publication number: 20130234151
    Abstract: According to one embodiment, a nitride semiconductor element includes a foundation layer, a functional layer and a stacked body. The stacked body is provided between the foundation layer and the functional layer. The stacked body includes a first stacked intermediate layer including a first GaN intermediate layer, a first high Al composition layer of Alx1Ga1-x1N (0<x1?1) and a first low Al composition layer. A compressive strain is applied to the first low Al composition layer. Unstrained GaN has a first lattice spacing. The Alx1Ga1-x1N (0<x1?1) when unstrained has a second lattice spacing. The first high Al composition layer has a third lattice spacing. An Al composition ratio of the first low Al composition layer is not more than a ratio of a difference between the first and third lattice spacings to a difference between the first and second lattice spacings.
    Type: Application
    Filed: September 4, 2012
    Publication date: September 12, 2013
    Applicant: Kabushiki Kaisha Toshiba
    Inventors: Toshiki HIKOSAKA, Yoshiyuki Harada, Hisashi Yoshida, Naoharu Sugiyama, Shinya Nunoue
  • Patent number: 8525203
    Abstract: According to one embodiment, a semiconductor light emitting device includes an n-type semiconductor layer, a p-type semiconductor layer, a light emitting portion, a first layer, a second layer, and an intermediate layer. The semiconductor layers include nitride semiconductor. The light emitting portion is provided between the n-type semiconductor layer and the p-type semiconductor layer and includes a quantum well layer. The first layer is provided between the light emitting portion and the p-type semiconductor layer and includes AlX1Ga1-x1N having first Al composition ratio x1. The second layer is provided between the first layer and the p-type semiconductor layer and includes Alx2Ga1-x2N having second Al composition ratio x2 higher than the first Al composition ratio x1. The intermediate layer is provided between the first layer and the light emitting portion and has a thickness not smaller than 3 nanometers and not larger than 8 nanometers and includes Inz1Ga1-z1N (0?z1<1).
    Type: Grant
    Filed: September 2, 2010
    Date of Patent: September 3, 2013
    Assignee: Kabushiki Kaisha Toshiba
    Inventors: Koichi Tachibana, Hajime Nago, Toshiki Hikosaka, Shigeya Kimura, Shinya Nunoue
  • Patent number: 8525195
    Abstract: According to one embodiment, a semiconductor light emitting device includes n-type and p-type semiconductor layers, a light emitting portion, a multilayered structural body, and an n-side intermediate layer. The light emitting portion is provided between the semiconductor layers. The light emitting portion includes barrier layers containing GaN, and a well layer provided between the barrier layers. The well layer contains Inx1Ga1-x1N. The body is provided between the n-type semiconductor layer and the light emitting portion. The body includes: first layers containing GaN, and a second layer provided between the first layers. The second layer contains Inx2Ga1-x2N. Second In composition ratio x2 is not less than 0.6 times of first In composition ratio x1 and is lower than the first In composition x1. The intermediate layer is provided between the body and the light emitting portion and includes a third layer containing Aly1Ga1-y1N (0<y1?0.01).
    Type: Grant
    Filed: September 1, 2010
    Date of Patent: September 3, 2013
    Assignee: Kabushiki Kaisha Toshiba
    Inventors: Hajime Nago, Koichi Tachibana, Toshiki Hikosaka, Shigeya Kimura, Shinya Nunoue
  • Patent number: 8525197
    Abstract: According to one embodiment, a semiconductor light emitting device includes an n-type semiconductor layer, a p-type semiconductor layer, and a light emitting part provided therebetween. The light emitting part includes a plurality of light emitting layers. Each of the light emitting layers includes a well layer region and a non-well layer region which is juxtaposed with the well layer region in a plane perpendicular to a first direction from the n-type semiconductor layer towards the p-type semiconductor layer. Each of the well layer regions has a common An In composition ratio. Each of the well layer regions includes a portion having a width in a direction perpendicular to the first direction of 50 nanometers or more.
    Type: Grant
    Filed: February 25, 2011
    Date of Patent: September 3, 2013
    Assignee: Kabushiki Kaisha Toshiba
    Inventors: Yoshiyuki Harada, Toshiki Hikosaka, Tomonari Shioda, Koichi Tachibana, Hajime Nago, Shinya Nunoue
  • Patent number: 8471277
    Abstract: A light emitting device according to one embodiment includes a light emitting element that emits light having a wavelength of 380 nm to 470 nm; a CASN first red phosphor that is disposed on the light emitting element; a sialon second red phosphor that is disposed on the light emitting element; and a sialon green phosphor that is disposed on the light emitting element.
    Type: Grant
    Filed: August 22, 2011
    Date of Patent: June 25, 2013
    Assignee: Kabushiki Kaisha Toshiba
    Inventors: Iwao Mitsuishi, Shinya Nunoue, Takahiro Sato, Yumi Fukuda, Aoi Okada, Naotoshi Matsuda, Toshiki Hikosaka, Keiko Albessard, Masahiro Kato
  • 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
  • Patent number: 8461606
    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: Grant
    Filed: September 3, 2010
    Date of Patent: June 11, 2013
    Assignee: Kabushiki Kaisha Toshiba
    Inventors: Shigeya Kimura, Hajime Nago, Toshiyuki Oka, Koichi Tachibana, Toshiki Hikosaka, Shinya Nunoue
  • Patent number: 8421108
    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: April 16, 2013
    Assignee: Kabushiki Kaisha Toshiba
    Inventors: Hiroshi Ono, Toshiki Hikosaka, Tomoko Morioka, Toshiyuki Oka, Shinya Nunoue
  • Publication number: 20130087760
    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, and a light emitting layer provided between the first semiconductor layer and the second semiconductor layer and configured to emit a light having a peak wavelength of 440 nanometers or more. Tensile strain is applied to the first semiconductor layer. An edge dislocation density of the first semiconductor layer is 5×109/cm2 or less. A lattice mismatch factor between the first semiconductor layer and the light emitting layer is 0.11 percent or less.
    Type: Application
    Filed: February 27, 2012
    Publication date: April 11, 2013
    Applicant: Kabushiki Kaisha Toshiba
    Inventors: Hisashi Yoshida, Koichi Tachibana, Tomonari Shioda, Toshiki Hikosaka, Jongil Hwang, Hung Hung, Naoharu Sugiyama, Shinya Nunoue
  • Publication number: 20130069098
    Abstract: According to one embodiment, a light emitting device includes a semiconductor light emitting element to emit a first light, a mounting member, first and second wavelength conversion layers and a transparent layer. The first wavelength conversion layer is provided between the element and the mounting member in contact with the mounting member. The first wavelength conversion layer absorbs the first light and emits a second light having a wavelength longer than a wavelength of the first light. The semiconductor light emitting element is disposed between the second wavelength conversion layer and the first wavelength conversion layer. The second wavelength conversion layer absorbs the first light and emits a third light having a wavelength longer than the wavelength of the first light. The transparent layer is provided between the element and the second wavelength conversion layer. The transparent layer is transparent to the first, second, and third lights.
    Type: Application
    Filed: November 15, 2012
    Publication date: March 21, 2013
    Inventors: Toshiki Hikosaka, Takahiro Sato, Iwao Mitsuishi, Shinya Nunoue