Patents by Inventor Hideto Sugawara

Hideto Sugawara 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: 6881601
    Abstract: A nitride compound semiconductor light-emitting device having a stack of layers including an active layer for a light emitting device and a method of manufacturing the device is disclosed. The method includes the steps of growing a first layer on a substrate at a first temperature to obtain an incomplete crystalline structure including both indium and aluminum and having the composition expressed as InXAlYGa1-X-YN(0?X?1, 0?Y?1). The method grows a cap layer on the first layer to cover the first layer, with growth of the cap layer proceeding at a second temperature substantially equal to or below the first temperature. The first layer is heat treated at a third temperature above the first temperature to cause the incomplete crystalline structure to crystallize and to create areas of differing compositions, thus changing the first layer to an active layer. The material of the cap layer is selected to be heat stable during the heat-treating step.
    Type: Grant
    Filed: January 30, 2003
    Date of Patent: April 19, 2005
    Assignee: Kabushiki Kaisha Toshiba
    Inventor: Hideto Sugawara
  • Publication number: 20050056857
    Abstract: An InGaN active layer is formed on a sapphire substrate. A p-side electrode is formed on the InGaN active layer to supply an electric current to this InGaN active layer. The p-side electrode includes {circle over (1)} an Ni layer for forming an ohmic contact with a p-GaN layer, {circle over (2)} an Mo layer having a barrier function of preventing diffusion of impurities, {circle over (3)} an Al layer as a high-reflection electrode, {circle over (4)} a Ti layer having a barrier function, and {circle over (5)} an Au layer for improving the contact with a submount on a lead frame. The p-side electrode having this five-layered structure realizes an ohmic contact and high reflectance at the same time.
    Type: Application
    Filed: October 4, 2004
    Publication date: March 17, 2005
    Inventors: Haruhiko Okazaki, Hideto Sugawara
  • Publication number: 20050051786
    Abstract: An InGaN active layer is formed on a sapphire substrate. A p-side electrode is formed on the InGaN active layer to supply an electric current to this InGaN active layer. The p-side electrode includes {circle over (1)} an Ni layer for forming an ohmic contact with a p-GaN layer, {circle over (2)} an Mo layer having a barrier function of preventing diffusion of impurities, {circle over (3)} an Al layer as a high-reflection electrode, {circle over (4)} a Ti layer having a barrier function, and {circle over (5)} an Au layer for improving the contact with a submount on a lead frame. The p-side electrode having this five-layered structure realizes an ohmic contact and high reflectance at the same time.
    Type: Application
    Filed: September 22, 2004
    Publication date: March 10, 2005
    Inventors: Haruhiko Okazaki, Hideto Sugawara
  • Publication number: 20050040420
    Abstract: An InGaN active layer is formed on a sapphire substrate. A p-side electrode is formed on the InGaN active layer to supply an electric current to this InGaN active layer. The p-side electrode includes {circle over (1)} an Ni layer for forming an ohmic contact with a p-GaN layer, {circle over (2)} an Mo layer having a barrier function of preventing diffusion of impurities, {circle over (3)} an Al layer as a high-reflection electrode, {circle over (4)} a Ti layer having a barrier function, and {circle over (5)} an Au layer for improving the contact with a submount on a lead frame. The p-side electrode having this five-layered structure realizes an ohmic contact and high reflectance at the same time.
    Type: Application
    Filed: October 4, 2004
    Publication date: February 24, 2005
    Inventors: Haruhiko Okazaki, Hideto Sugawara
  • Publication number: 20050040423
    Abstract: An InGaN active layer is formed on a sapphire substrate. A p-side electrode is formed on the InGaN active layer to supply an electric current to this InGaN active layer. The p-side electrode includes {circumflex over (1)} an Ni layer for forming an ohmic contact with a p-GaN layer, {circumflex over (2)} an Mo layer having a barrier function of preventing diffusion of impurities, {circumflex over (3)} an Al layer as a high-reflection electrode, {circumflex over (4)} a Ti layer having a barrier function, and {circumflex over (5)} an Au layer for improving the contact with a submount on a lead frame. The p-side electrode having this five-layered structure realizes an ohmic contact and high reflectance at the same time.
    Type: Application
    Filed: September 22, 2004
    Publication date: February 24, 2005
    Inventors: Haruhiko Okazaki, Hideto Sugawara
  • Publication number: 20050040427
    Abstract: There are provided a semiconductor light emitting device wherein the variation in tone in each device is small and the variation in tone due to deterioration with age is also small, and a method for manufacturing the same. The semiconductor light emitting device includes an active layer for emitting primary light having a first wavelength by current injection, and a light emitting layer excited by the primary light for emitting secondary light having a second wavelength different from said first wavelength, wherein the primary light and the secondary light are mixed to be outputted.
    Type: Application
    Filed: September 30, 2004
    Publication date: February 24, 2005
    Inventors: Hideto Sugawara, Koichi Nitta, Hirohisa Abe, Kuniaki Konno, Yasuo Idei
  • Publication number: 20050037527
    Abstract: An InGaN active layer is formed on a sapphire substrate. A p-side electrode is formed on the InGaN active layer to supply an electric current to this InGaN active layer. The p-side electrode includes {circle over (1)} an Ni layer for forming an ohmic contact with a p-GaN layer, {circle over (2)} an Mo layer having a barrier function of preventing diffusion of impurities, {circle over (3)} an Al layer as a high-reflection electrode, {circle over (4)} a Ti layer having a barrier function, and {circle over (5)} an Au layer for improving the contact with a submount on a lead frame. The p-side electrode having this five-layered structure realizes an ohmic contact and high reflectance at the same time.
    Type: Application
    Filed: September 21, 2004
    Publication date: February 17, 2005
    Inventors: Haruhiko Okazaki, Hideto Sugawara
  • Publication number: 20050035363
    Abstract: An InGaN active layer is formed on a sapphire substrate. A p-side electrode is formed on the InGaN active layer to supply an electric current to this InGaN active layer. The p-side electrode includes {circle over (1)} an Ni layer for forming an ohmic contact with a p-GaN layer, {circle over (2)} an Mo layer having a barrier function of preventing diffusion of impurities, {circle over (3)} an Al layer as a high-reflection electrode, {circle over (4)} a Ti layer having a barrier function, and {circle over (5)} an Au layer for improving the contact with a submount on a lead frame. The p-side electrode having this five-layered structure realizes an ohmic contact and high reflectance at the same time.
    Type: Application
    Filed: September 22, 2004
    Publication date: February 17, 2005
    Inventors: Haruhiko Okazaki, Hideto Sugawara
  • Patent number: 6846686
    Abstract: A semiconductor light-emitting device, including a first substrate of a first conductivity type, a first bonding layer provided on the first substrate and consisting essentially of a GaP material of the first conductivity type, a second bonding layer provided on the first bonding layer, coincident with the first bonding layer in the planar direction of the crystal, having the first conductivity type, and consisting essentially of a material represented by a formula InxGayP, where 0?x, y?1, and x+y=1, and a light-emitting layer comprising a first cladding layer, an active layer, and a second cladding layer, which are successively provided on the second bonding layer, each of the active layer and first and second cladding layers consisting essentially of a material represented by a formula InxGayAlzP, where x+y+z=1, and 0?x, y, z?1.
    Type: Grant
    Filed: May 5, 2003
    Date of Patent: January 25, 2005
    Assignee: Kabushiki Kaisha Toshiba
    Inventors: Ryo Saeki, Hideto Sugawara, Yukio Watanabe, Tamotsu Jitosho
  • Patent number: 6828593
    Abstract: When a plurality of semiconductor layers including a nitride compound layer containing indium are stacked on a substrate, materials of layers above the indium containing nitride compound layer are limited to specific compounds, or their growth temperatures are limited within a predetermined range, to suppress thermal deterioration of the nitride compound layer containing indium or deterioration of the interface and to thereby grow a high-quality semiconductor light emitting element using nitride compound semiconductors.
    Type: Grant
    Filed: April 18, 2002
    Date of Patent: December 7, 2004
    Assignee: Kabushiki Kaisha Toshiba
    Inventors: Hideto Sugawara, Masayuki Ishikawa
  • Patent number: 6825502
    Abstract: An InGaN active layer is formed on a sapphire substrate. A p-side electrode is formed on the InGaN active layer to supply an electric current to this InGaN active layer. The p-side electrode includes {circle around (1)} an Ni layer for forming an ohmic contact with a p-GaN layer, {circle around (2)} an Mo layer having a barrier function of preventing diffusion of impurities, {circle around (3)} an Al layer as a high-reflection electrode, {circle around (4)} a Ti layer having a barrier function, and {circle around (5)} an Au layer for improving the contact with a submount on a lead frame. The p-side electrode having this five-layered structure realizes an ohmic contact and high reflectance at the same time.
    Type: Grant
    Filed: April 17, 2003
    Date of Patent: November 30, 2004
    Assignee: Kabushiki Kaisha Toshiba
    Inventors: Haruhiko Okazaki, Hideto Sugawara
  • Patent number: 6815725
    Abstract: There are provided a semiconductor light emitting device wherein the variation in tone in each device is small and the variation in tone due to deterioration with age is also small, and a method for manufacturing the same. The semiconductor light emitting device includes an active layer for emitting primary light having a first wavelength by current injection, and a light emitting layer excited by the primary light for emitting secondary light having a second wavelength different from said first wavelength, wherein the primary light and the secondary light are mixed to be outputted.
    Type: Grant
    Filed: April 17, 2003
    Date of Patent: November 9, 2004
    Assignee: Kabushiki Kaisha Toshiba
    Inventors: Hideto Sugawara, Koichi Nitta, Hirohisa Abe, Kuniaki Konno, Yasuo Idei
  • Publication number: 20040206966
    Abstract: A group-III nitride semiconductor stack comprises a single-crystal substrate, a first group-III nitride layer formed on a principal surface of the single-crystal substrate, a graded low-temperature deposited layer formed on the group-III nitride layer and made of nitride in which group-III element composition is continuously changed, and a second group-III nitride layer formed on the graded low-temperature deposited layer.
    Type: Application
    Filed: March 23, 2004
    Publication date: October 21, 2004
    Applicant: KABUSHIKI KAISHA TOSHIBA
    Inventors: Hideto Sugawara, Tsunenori Hiratsuka
  • Patent number: 6791118
    Abstract: There is disclosed a semiconductor light emitting element formed by selective growth and being high in light emitting efficiency, in which at least one GaN-based layer grown by ELO in stacked/formed on a sapphire substrate, and a fluorescent substance for converting an ultraviolet light to a visible light is contained in a selective growth mask material layer for use in this case. Since this fluorescent substance converts the ultraviolet light to the visible light, a binding efficiency of the ultraviolet light to the fluorescent substance is enhanced in either one of a center light emitting type and UV light emitting type of light emitting elements. By further containing the fluorescent substance into a passivation film, the efficiency is further enhanced.
    Type: Grant
    Filed: June 23, 2003
    Date of Patent: September 14, 2004
    Assignee: Kabushiki Kaisha Toshiba
    Inventors: Chisato Furukawa, Hideto Sugawara, Nobuhir Suzuki
  • Publication number: 20040119082
    Abstract: Nitride based semiconductor light-emitting devices with a sufficiently low contact resistance p-type electrode and a method of manufacturing the same are disclosed. One such method of manufacturing nitride based semiconductor light-emitting devices includes steps of growing island-like AlGaN films 17 on p-type nitride based semiconductor layer 16, etching a surface of p-type type nitride based semiconductor layer 16 to make uneven portions 18 on its surface by using island-like AlGaN films 17 as a photomask, and forming of a p-type ohmic electrode on an electrode forming region of the uneven portion 18.
    Type: Application
    Filed: December 9, 2003
    Publication date: June 24, 2004
    Applicant: KABUSHIKI KAISHA TOSHIBA
    Inventor: Hideto Sugawara
  • Publication number: 20040079955
    Abstract: There is disclosed a semiconductor light emitting element formed by selective growth and being high in light emitting efficiency, in which at least one GaN-based layer grown by ELO is stacked/formed on a sapphire substrate, and a fluorescent substance for converting an ultraviolet light to a visible light is contained in a selective growth mask material layer for use in this case. Since this fluorescent substance converts the ultraviolet light to the visible light, a binding efficiency of the ultraviolet light to the fluorescent substance is enhanced in either one of a center light emitting type and UV light emitting type of light emitting elements. By further containing the fluorescent substance into a passivation film, the efficiency is further enhanced.
    Type: Application
    Filed: June 23, 2003
    Publication date: April 29, 2004
    Applicant: KABUSHIKI KAISHA TOSHIBA
    Inventors: Chisato Furukawa, Hideto Sugawara, Nobuhiro Suzuki
  • Patent number: 6693307
    Abstract: In a light emitting element using nitride compound semiconductors, an active layer made of a mixed crystal containing In additionally contains at least Al or B as a component of the mixed crystal to improve the thermal resistance of the crystal and the reliability of the element characteristics. Thus, the semiconductor light emitting element has a sufficient lifetime and permits the emission wavelength to be freely selected from a wider wavelength range including blue, green and orange.
    Type: Grant
    Filed: November 2, 2001
    Date of Patent: February 17, 2004
    Assignee: Kabushiki Kaisha Toshiba
    Inventors: Hideto Sugawara, Koichi Nitta
  • Patent number: 6674097
    Abstract: A light emitting device or image display includes a fluorescent material as a wavelength converter for converting a wavelength into another. The fluorescent material is disposed in a predetermined positional relation, to prevent external leakage of primary light and to extract secondary light made by wavelength-converting the primary light with a very high efficiency. By using a semiconductor light emitting element for ultraviolet emission and combining it with a fluorescent material or any other appropriate material having a wavelength converting function, various kinds of applications, such as illuminator, having a remarkably long-life light source can be made. The semiconductor light emitting element preferably has a emission wavelength near 330 nm, and preferably uses BGaN in its light emitting layer.
    Type: Grant
    Filed: October 24, 2001
    Date of Patent: January 6, 2004
    Assignee: Kabushiki Kaisha Toshiba
    Inventors: Satoshi Komoto, Koichi Nitta, Nobuhiro Suzuki, Kuniaki Konno, Hideto Sugawara, Chisato Furukawa
  • Patent number: 6661030
    Abstract: A light emitting device or image display includes a fluorescent material as a wavelength converter for converting a wavelength into another. The fluorescent material is disposed in a predetermined positional relation, to prevent external leakage of primary light and to extract secondary light made by wavelength-converting the primary light with a very high efficiency. By using a semiconductor light emitting element for ultraviolet emission and combining it with a fluorescent material or any other appropriate material having a wavelength converting function, various kinds of applications, such as illuminator, having a remarkably long-life light source can be made. The semiconductor light emitting element preferably has a emission wavelength near 330 nm, and preferably uses BGaN in its light emitting layer.
    Type: Grant
    Filed: October 23, 2001
    Date of Patent: December 9, 2003
    Assignee: Kabushiki Kaisha Toshiba
    Inventors: Satoshi Komoto, Koichi Nitta, Nobuhiro Suzuki, Kuniaki Konno, Hideto Sugawara, Chisato Furukawa
  • Publication number: 20030218172
    Abstract: A high-luminance light emitting element is manufactured by a method comprising: forming a light emitting layer on a first surface of a GaP substrate including the first surface and a second surface opposed to the first surface and having an area smaller than the first area, the light emitting layer emitting light of a wavelength &lgr; permitted to pass through the GaP substrate; forming a plurality of side surfaces on the GaP substrate to be respectively aslant by substantially the same angle to become narrower toward the second surface; and forming a plurality of depressions and protrusions as high as 0.1 &lgr; to 3 &lgr; on the side surfaces.
    Type: Application
    Filed: April 4, 2003
    Publication date: November 27, 2003
    Applicant: KABUSHIKI KAISHA TOSHIBA
    Inventors: Hideto Sugawara, Yukio Watanabe, Hirohisa Abe, Kuniaki Konno