Patents by Inventor Hajime Nago

Hajime Nago 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).

  • 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: 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: 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
  • 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: 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: 20110204411
    Abstract: According to one embodiment, a crystal growth method is disclosed for growing a crystal of a nitride semiconductor on a major surface of a substrate. The major surface is provided with asperities. The method can include depositing a buffer layer on the major surface at a rate of not more than 0.1 micrometers per hour. The buffer layer includes GaxAl1-xN (0.1?x<0.5) and has a thickness of not smaller than 20 nanometers and not larger than 50 nanometers. In addition, the method can include growing the crystal including a nitride semiconductor on the buffer layer at a temperature higher than a temperature of the substrate in the depositing the buffer layer.
    Type: Application
    Filed: September 3, 2010
    Publication date: August 25, 2011
    Applicant: Kabushiki Kaisha Toshiba
    Inventors: Hajime NAGO, Koichi TACHIBANA, Toshiki HIKOSAKA, 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
  • Publication number: 20110198633
    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 portion. The light emitting portion is provided between the semiconductor layers and includes barrier layers and well layers alternately stacked. An n-side end well layer which is closest to the n-type semiconductor layer contains InwnGa1-wnN and has a layer thickness twn. An n-side end barrier layer which is closest to the n-type semiconductor layer contains InbnGa1-bnN and has a layer thickness tbn. A p-side end well layer which is closest to the p-type semiconductor layer contains InwpGa1-wpN and has a layer thickness twp. A p-side end barrier layer which is closest to the p-type semiconductor contains InbpGa1-bpN and has a layer thickness tbp. A value of (wp×twp+bp×tbp)/(twp+tbp) is higher than (wn×twn+bn×tbn)/(twn+tbn) and is not higher than 5 times (wn×twn+bn×tbn)/(twn+tbn).
    Type: Application
    Filed: August 30, 2010
    Publication date: August 18, 2011
    Applicant: Kabushiki Kaisha Toshiba
    Inventors: Koichi TACHIBANA, Toshiki Hikosaka, Shigeya Kimura, Hajime Nago, Shinya Nunoue
  • Publication number: 20110198583
    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: Application
    Filed: September 1, 2010
    Publication date: August 18, 2011
    Applicant: Kabushiki Kaisha Toshiba
    Inventors: Hajime NAGO, Koichi Tachibana, Toshiki Hikosaka, Shigeya Kimura, Shinya Nunoue
  • Publication number: 20110198561
    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: September 2, 2010
    Publication date: August 18, 2011
    Applicant: Kabushiki Kaisha Toshiba
    Inventors: Koichi TACHIBANA, Hajime Nago, Toshiki Hikosaka, Shigeya Kimura, Shinya Nunoue
  • Publication number: 20110143463
    Abstract: According to one embodiment, a vapor deposition method is disclosed for forming a nitride semiconductor layer on a substrate by supplying a group III source-material gas and a group V source-material gas. The method can deposit a first semiconductor layer including a nitride semiconductor having a compositional proportion of Al in group III elements of not less than 10 atomic percent by supplying the group III source-material gas from a first outlet and by supplying the group V source-material gas from a second outlet. The method can deposit a second semiconductor layer including a nitride semiconductor having a compositional proportion of Al in group III elements of less than 10 atomic percent by mixing the group III and group V source-material gases and supplying the mixed group III and group V source-material gases from at least one of the first outlet and the second outlet.
    Type: Application
    Filed: September 3, 2010
    Publication date: June 16, 2011
    Applicant: Kabushiki Kaisha Toshiba
    Inventors: Yoshiyuki HARADA, Koichi Tachibana, Toshiki Hikosaka, Hajime Nago, Shinya Nunoue
  • Publication number: 20110068360
    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: Application
    Filed: November 29, 2010
    Publication date: March 24, 2011
    Applicant: KABUSHIKI KAISHA TOSHIBA
    Inventors: Hajime NAGO, Koichi Tachibana, Kotaro Zaima, Shinji Saito, Shinya Nunoue, Toshiyuki Oka
  • Publication number: 20110037049
    Abstract: Disclosed is a nitride semiconductor light-emitting device including a substrate, a pair of p-type and n-type clad layers formed on the substrate, and an active layer having a single quantum well structure or a multiple quantum well structure, which is sandwiched between the p-type clad layer and the n-type clad layer, and includes a quantum well layer and a pair of barrier layers each having a larger bandgap than that of the quantum well layer, the quantum well layer being sandwiched between the pair of barrier layers. Each of the pair of barrier layers has a multi-layer structure including, starting from the quantum well layer side, a first subbarrier layer having a composition of Iny1Ga1-y1N, a second subbarrier layer having a composition of Iny2Ga1-y2N and a third subbarrier layer having a composition of Iny3Ga1-y3N, in which y1, y2 and y3 satisfy the relationship of 0?y1,y3<y2<1 and y1=y3.
    Type: Application
    Filed: March 4, 2010
    Publication date: February 17, 2011
    Inventors: Koichi TACHIBANA, Hajime Nago, Toshiki Hikosaka, Shinya Nunoue
  • Patent number: 7863637
    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: February 26, 2008
    Date of Patent: January 4, 2011
    Assignee: Kabushiki Kaisha Toshiba
    Inventors: Hajime Nago, Koichi Tachibana, Kotaro Zaima, Shinji Saito, Shinya Nunoue, Toshiyuki Oka
  • Publication number: 20100187497
    Abstract: A semiconductor device includes an underlying layer, and a light emitting layer which is formed on the underlying layer and in which a barrier layer made of InAlGaN and a quantum well layer made of InGaN are alternately stacked.
    Type: Application
    Filed: March 3, 2010
    Publication date: July 29, 2010
    Inventors: Hajime NAGO, Koichi Tachibana, Shinji Saito, Yoshiyuki Harada, Shinya Nunoue
  • Patent number: 7763907
    Abstract: A semiconductor light emitting element includes: an {0001} n-type semiconductor substrate formed of a III-V semiconductor, which is in a range of 0° to 45° in inclination angle into a <1-100> direction, and which is in a range of 0° to 10° in inclination angle into a <11-20> direction; an n-type layer formed of a III-V semiconductor on the n-type semiconductor substrate; an n-type guide layer formed of a III-V semiconductor above the n-type layer; an active layer formed of a III-V semiconductor above the n-type guide layer; a p-type first guide layer formed of a III-V semiconductor above the active layer; a p-type contact layer formed of a III-V semiconductor above the p-type first guide layer; and an concavo-convex layer formed of a III-V semiconductor between the p-type first guide layer and the p-type contact layer.
    Type: Grant
    Filed: September 5, 2007
    Date of Patent: July 27, 2010
    Assignee: Kabushiki Kaisha Toshiba
    Inventors: Koichi Tachibana, Hajime Nago, Shinji Saito, Shinya Nunoue, Genichi Hatakoshi
  • Publication number: 20100102296
    Abstract: A semiconductor device has an active layer, a first semiconductor layer of first conductive type, an overflow prevention layer disposed between the active layer and the first semiconductor layer, which is doped with impurities of first conductive type and which prevents overflow of electrons or holes, a second semiconductor layer of first conductive type disposed at least one of between the active layer and the overflow prevention layer and between the overflow prevention layer and the first semiconductor layer, and an impurity diffusion prevention layer disposed between the first semiconductor layer and the active layer, which has a band gap smaller than those of the overflow prevention layer, the first semiconductor layer and the second semiconductor layer and which prevents diffusion of impurities of first conductive type.
    Type: Application
    Filed: January 6, 2010
    Publication date: April 29, 2010
    Applicant: Kabushiki Kaisha Toshiba
    Inventors: Koichi TACHIBANA, Chie HONGO, Hajime NAGO, Shinya NUNOUE
  • Patent number: 7683390
    Abstract: A semiconductor device has an active layer, a first semiconductor layer of first conductive type, an overflow prevention layer disposed between the active layer and the first semiconductor layer, which is doped with impurities of first conductive type and which prevents overflow of electrons or holes, a second semiconductor layer of first conductive type disposed at least one of between the active layer and the overflow prevention layer and between the overflow prevention layer and the first semiconductor layer, and an impurity diffusion prevention layer disposed between the first semiconductor layer and the active layer, which has a band gap smaller than those of the overflow prevention layer, the first semiconductor layer and the second semiconductor layer and which prevents diffusion of impurities of first conductive type.
    Type: Grant
    Filed: February 25, 2008
    Date of Patent: March 23, 2010
    Assignee: Kabushiki Kaisha Toshiba
    Inventors: Koichi Tachibana, Chie Hongo, Hajime Nago, Shinya Nunoue
  • Publication number: 20080237569
    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: Application
    Filed: February 26, 2008
    Publication date: October 2, 2008
    Applicant: KABUSHIKI KAISHA TOSHIBA
    Inventors: Hajime NAGO, Koichi Tachibana, Kotaro Zaima, Shinji Saito, Shinya Nunoue, Toshiyuki Oka