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: 8399896
    Abstract: According to one embodiment, a semiconductor light emitting device includes n-type and p-type semiconductor layers, barrier layers, and a well layer. The n-type and p-type semiconductor layers and the barrier layers include nitride semiconductor. The barrier layers are provided between the n-type and p-type semiconductor layers. The well layer is provided between the barrier layers, has a smaller band gap energy than the barrier layers, and includes InGaN. At least one of the barrier layers includes first, second, and third layers. The second layer is provided closer to the p-type semiconductor layer than the first layer. The third layer is provided closer to the p-type semiconductor layer than the second layer. The second layer includes AlxGa1?xN (0<x?0.05). A band gap energy of the second layer is larger than the first and third layers. A total thickness of the first and second layers is not larger than the third layer.
    Type: Grant
    Filed: September 3, 2010
    Date of Patent: March 19, 2013
    Assignee: Kabushiki Kaisha Toshiba
    Inventors: Toshiki Hikosaka, Tomonari Shioda, Yoshiyuki Harada, Shinya Nunoue
  • Patent number: 8395169
    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: September 2, 2010
    Date of Patent: March 12, 2013
    Assignee: Kabushiki Kaisha Toshiba
    Inventors: Toshiki Hikosaka, Takahiro Sato, Iwao Mitsuishi, Shinya Nunoue
  • Patent number: 8368104
    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: September 2, 2010
    Date of Patent: February 5, 2013
    Assignee: Kabushiki Kaisha Toshiba
    Inventors: Toshiki Hikosaka, Takahiro Sato, Iwao Mitsuishi, Shinya Nunoue
  • Publication number: 20120299014
    Abstract: According to one embodiment, a semiconductor light emitting device includes a first semiconductor layer of a first conductivity type and having a major surface, a second semiconductor layer of a second conductivity type, and a light emitting layer provided between the first and second semiconductor layers. The major surface is opposite to the light emitting layer. The first semiconductor layer has structural bodies provided in the major surface. The structural bodies are recess or protrusion. A centroid of a first structural body aligns with a centroid of a second structural body nearest the first structural. hb, rb, and Rb satisfy rb/(2·hb)?0.7, and rb/Rb<1, where hb is a depth of the recess, rb is a width of a bottom portion of the recess, and Rb is a width of the protrusion.
    Type: Application
    Filed: February 24, 2012
    Publication date: November 29, 2012
    Applicant: Kabushiki Kaisha Toshiba
    Inventors: Toshiki HIKOSAKA, Yoshiyuki Harada, Maki Sugai, Shinya Nunoue
  • Publication number: 20120299015
    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: Application
    Filed: February 27, 2012
    Publication date: November 29, 2012
    Applicant: Kabushiki Kaisha Toshiba
    Inventors: Koichi TACHIBANA, Hisashi Yoshida, Hiroshi Ono, Hajime Nago, Yoshiyuki Harada, Toshiki Hikosaka, Maki Sugai, Toshiyuki Oka, Shinya Nunoue
  • Publication number: 20120298952
    Abstract: According to an embodiment, a semiconductor light emitting device includes a foundation layer, a first semiconductor layer, a light emitting layer, and a second semiconductor layer. The foundation layer has an unevenness having recesses, side portions, and protrusions. A first major surface of the foundation layer has an overlay-region. The foundation layer has a plurality of dislocations including first dislocations whose one ends reaching the recess and second dislocations whose one ends reaching the protrusion. A proportion of a number of the second dislocations reaching the first major surface to a number of all of the second dislocations is smaller than a proportion of a number of the first dislocations reaching the first major surface to a number of all of the first dislocations. A number of the dislocations reaching the overlay-region of the first major surface is smaller than a number of all of the first dislocations.
    Type: Application
    Filed: February 28, 2012
    Publication date: November 29, 2012
    Applicant: Kabushiki Kaisha Toshiba
    Inventors: Toshiki HIKOSAKA, Yoshiyuki HARADA, Maki SUGAI, Shinya NUNOUE
  • Publication number: 20120295377
    Abstract: According to one embodiment, a method is disclosed for manufacturing a nitride semiconductor device. The method can include removing a growth substrate from a structure body by using a first treatment material. The structure body has the growth substrate, a buffer layer formed on the growth substrate, and the nitride semiconductor layer formed on the buffer layer. A support substrate is bonded to the nitride semiconductor layer. The method can include reducing thicknesses of the buffer layer and the nitride semiconductor layer by using a second treatment material different from the first treatment material after removing the growth substrate.
    Type: Application
    Filed: August 31, 2011
    Publication date: November 22, 2012
    Applicant: Kabushiki Kaisha Toshiba
    Inventors: Taisuke SATO, Naoharu SUGIYAMA, Tomonari SHIODA, Toshiki HIKOSAKA, Shinya NUNOUE
  • Patent number: 8310145
    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: February 24, 2011
    Date of Patent: November 13, 2012
    Assignee: Kabushiki Kaisha Toshiba
    Inventors: Iwao Mitsuishi, Shinya Nunoue, Takahiro Sato, Yumi Fukuda, Aoi Okada, Naotoshi Matsuda, Toshiki Hikosaka
  • Publication number: 20120138890
    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: Application
    Filed: August 19, 2011
    Publication date: June 7, 2012
    Applicant: KABUSHIKI KAISHA TOSHIBA
    Inventors: Tomonari SHIODA, Toshiki Hikosaka, Yoshiyuki Harada, Naoharu Sugiyama, Shinya Nunoue
  • Publication number: 20120138985
    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: Application
    Filed: August 12, 2011
    Publication date: June 7, 2012
    Applicant: Kabushiki Kaisha Toshiba
    Inventors: Hiroshi ONO, Toshiki HIKOSAKA, Tomoko MORIOKA, Toshiyuki OKA, Shinya NUNOUE
  • Publication number: 20120138889
    Abstract: According to one embodiment, a semiconductor light emitting device includes an n-type semiconductor layer, a p-type semiconductor layer, a light emitting part, and a p-side electrode. The light emitting part is provided between the n-type and the p-type semiconductor layers, and includes a plurality of barrier layers and a plurality of well layers. The p-side electrode contacts the p-type semiconductor layer. The p-type semiconductor layer includes first, second, third, and fourth p-type layers. The first p-type layer contacts the p-side electrode. The second p-type layer contacts the light emitting part. The third p-type layer is provided between the first p-type layer and the second p-type layer. The fourth p-type layer is provided between the second p-type layer and the third p-type layer. The second p-type layer contains Al and contains a p-type impurity in a lower concentration lower than that in the first concentration.
    Type: Application
    Filed: August 4, 2011
    Publication date: June 7, 2012
    Applicant: KABUSHIKI KAISHA TOSHIBA
    Inventors: Koichi TACHIBANA, Hajime Nago, Toshiki Hikosaka, Shigeya Kimura, Shinya Nunoue
  • Publication number: 20120132943
    Abstract: According to one embodiment, a semiconductor light emitting device includes an n-type semiconductor layer, an electrode, a p-type semiconductor layer and a light emitting layer. The p-type semiconductor layer is provided between the n-type semiconductor layer and the electrode and includes a p-side contact layer contacting the electrode. The light emitting layer is provided between the n-type and the p-type semiconductor layers. The p-side contact layer includes a flat part having a plane perpendicular to a first direction from the n-type semiconductor layer toward the p-type semiconductor layer and multiple protruding parts protruding from the flat part toward the electrode. A height of the multiple protruding parts along the first direction is smaller than one-fourth of a dominant wavelength of light emitted from the light emitting layer. A density of the multiple protruding parts in the plane is 5×107/cm2 or more and 2×108/cm2 or less.
    Type: Application
    Filed: August 5, 2011
    Publication date: May 31, 2012
    Applicant: KABUSHIKI KAISHA TOSHIBA
    Inventors: Toshiki HIKOSAKA, Hajime Nago, Koichi Tachibana, Toshihide Ito, 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: 20120056526
    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: Application
    Filed: February 24, 2011
    Publication date: March 8, 2012
    Applicant: KABUSHIKI KAISHA TOSHIBA
    Inventors: Iwao MITSUISHI, Shinya Nunoue, Takahiro Sato, Yumi Fukuda, Aoi Okada, Naotoshi Matsuda, Toshiki Hikosaka
  • Publication number: 20120056224
    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: Application
    Filed: August 22, 2011
    Publication date: March 8, 2012
    Applicant: KABUSHIKI KAISHA TOSHIBA
    Inventors: Iwao MITSUISHI, Shinya Nunoue, Takahiro Sato, Yumi Fukuda, Aoi Okada, Naotoshi Matsuda, Toshiki Hikosaka, Keiko Albessard, Masahiro Kato
  • Publication number: 20120056157
    Abstract: According to one embodiment, a semiconductor light emitting device includes an n-type layer, a p-type layer, and a light emitting unit provided between the n-type layer and the p-type layer and including barrier layers and well layers. At least one of the barrier layers includes first and second portion layers. The first portion layer is disposed on a side of the n-type layer. The second portion layer is disposed on a side of the p-type layer, and contains n-type impurity with a concentration higher than that in the first portion layer. At least one of the well layers includes third and fourth portion layers. The third portion layer is disposed on a side of the n-type layer. The fourth portion layer is disposed on a side of the p-type layer, and contains n-type impurity with a concentration higher than that in the third portion layer.
    Type: Application
    Filed: August 31, 2011
    Publication date: March 8, 2012
    Applicant: Kabushiki Kaisha Toshiba
    Inventors: Toshiki Hikosaka, Koichi Tachibana, Hajime Nago, Shinya Nunoue
  • Publication number: 20120049155
    Abstract: According to one embodiment, a semiconductor light emitting device includes a first semiconductor layer, a second semiconductor layer, a light emitting part, and a multilayered structural body. The light emitting part is provided between the first and second semiconductor layers and includes barrier layers and well layers alternately stacked. The multilayered structural body is provided between the first semiconductor layer and the light emitting part and includes high energy layers and low energy layers alternately stacked. An average In composition ratio on a side of the second semiconductor is higher than that on a side of the first semiconductor in the multilayered structural body. An average In composition ratio on a side of the second semiconductor is higher than that on a side of the first semiconductor in the light emitting part.
    Type: Application
    Filed: February 18, 2011
    Publication date: March 1, 2012
    Applicant: KABUSHIKI KAISHA TOSHIBA
    Inventors: Koichi TACHIBANA, Hajime Nago, Toshiki Hikosaka, Shigeya Kimura, Shinya Nunoue
  • Publication number: 20120032209
    Abstract: According to one embodiment, a semiconductor light emitting device includes: semiconductor layers; a multilayered structural body; and a light emitting portion. The multilayered structural body is provided between the semiconductor layers, and includes a first layer and a second layer including In. The light emitting portion is in contact with the multilayered structural body between the multilayered structural body and p-type semiconductor layer, and includes barrier layers and a well layer including In with an In composition ratio among group III elements higher than an In composition ratio among group III elements in the second layer. An average lattice constant of the multilayered structural body is larger than that of the n-type semiconductor layer. Difference between the average lattice constant of the multilayered structural body and that of the light emitting portion is less than difference between that of the multilayered structural body and that of the n-type semiconductor layer.
    Type: Application
    Filed: February 23, 2011
    Publication date: February 9, 2012
    Applicant: KABUSHIKI KAISHA TOSHIBA
    Inventors: Tomonari SHIODA, Toshiki Hikosaka, Yoshiyuki Harada, Koichi Tachibana, Shinya Nunoue
  • Publication number: 20120012814
    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: February 25, 2011
    Publication date: January 19, 2012
    Applicant: Kabushiki Kaisha Toshiba
    Inventors: Yoshiyuki HARADA, Toshiki Hikosaka, Tomonari Shioda, Koichi Tachibana, Hajime Nago, Shinya Nunoue
  • Patent number: 8093083
    Abstract: In one embodiment, a method is disclosed for manufacturing a semiconductor light emitting device. The device includes a crystal layer including a nitride semiconductor. The crystal layer contains In and Ga atoms. The method can include forming the crystal layer by supplying a source gas including a first molecule including Ga atoms and a second molecule including In atoms onto a base body. The crystal layer has a ratio xs of a number of the In atoms to a total of the In atoms and the Ga atoms being not less than 0.2 and not more than 0.4. A vapor phase supply ratio xv of In is a ratio of a second partial pressure to a total of first and second partial pressures. The first and second partial pressures are pressure of the first and second molecules and degradation species of the first and second molecules on the source gas, respectively. (1?1/xv)/(1?1/xs) is less than 0.1.
    Type: Grant
    Filed: February 17, 2011
    Date of Patent: January 10, 2012
    Assignee: Kabushiki Kaisha Toshiba
    Inventors: Toshiki Hikosaka, Tomonari Shioda, Yoshiyuki Harada, Naoharu Sugiyama, Koichi Tachibana, Shinya Nunoue