Patents by Inventor Yoshihiro Ueta

Yoshihiro Ueta 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: 9099586
    Abstract: To provide a nitride semiconductor light-emitting element in which a buffer layer provided between an n-type nitride semiconductor layer and a p-type nitride semiconductor layer has a first buffer layer expressed by an equation of Inx1Ga1-x1N (0<x1?1) and a second buffer layer expressed by an equation of Inx2Ga1-x2N (0?x2<1, x2<x1) alternately laminated, an In composition x1 of the first buffer layer is changed, and the In composition x1 of at least one layer of the first buffer layers is higher than an In composition of the active layer, and a method for producing the same.
    Type: Grant
    Filed: November 19, 2012
    Date of Patent: August 4, 2015
    Assignee: SHARP KABUSHIKI KAISHA
    Inventors: Masaya Ueda, Yoshihiro Ueta, Yuichi Sano, Toshiyuki Okumura
  • Patent number: 8816321
    Abstract: A nitride semiconductor light-emitting device includes an n-type nitride semiconductor layer, a V pit generation layer, an intermediate layer, a multiple quantum well light-emitting layer, and a p-type nitride semiconductor layer provided in this order. The multiple quantum well light-emitting layer is a layer formed by alternately stacking a barrier layer and a well layer having a bandgap energy smaller than that of the barrier layer. A V pit is partly formed in the multiple quantum well light-emitting layer, and an average position of starting point of the V pit is located in the intermediate layer.
    Type: Grant
    Filed: August 13, 2012
    Date of Patent: August 26, 2014
    Assignee: Sharp Kabushiki Kaisha
    Inventors: Tadashi Takeoka, Yoshihiko Tani, Kazuya Araki, Yoshihiro Ueta
  • Patent number: 8698168
    Abstract: A method of crystal growth is provided which can suppress development of dislocations and cracks and a warp in a substrate. The method of crystal growth of a group III nitride semiconductor has: a step of heating a silicon substrate; and a step of forming a depressed structure on the substrate surface by advance-feeding onto the heated silicon substrate a gas containing at least TMA (trimethylaluminum).
    Type: Grant
    Filed: March 3, 2011
    Date of Patent: April 15, 2014
    Assignees: Sharp Kabushiki Kaisha, The Ritsumeikan Trust
    Inventors: Yoshihiro Ueta, Masataka Ohta, Yoshinobu Aoyagi, Misaichi Takeuchi
  • Patent number: 8502238
    Abstract: A nitride semiconductor laser device with a reduction in internal crystal defects and an alleviation in stress, and a semiconductor optical apparatus comprising this nitride semiconductor laser device. First, a growth suppressing film against GaN crystal growth is formed on the surface of an n-type GaN substrate equipped with alternate stripes of dislocation concentrated regions showing a high density of crystal defects and low-dislocation regions so as to coat the dislocation concentrate regions. Next, the n-type GaN substrate coated with the growth suppressing film is overlaid with a nitride semiconductor layer by the epitaxial growth of GaN crystals. Further, the growth suppressing film is removed to adjust the lateral distance between a laser waveguide region and the closest dislocation concentrated region to 40 ?m or more.
    Type: Grant
    Filed: November 28, 2012
    Date of Patent: August 6, 2013
    Assignees: Sharp Kabushiki Kaisha, Sumitomo Electric Industries, Ltd.
    Inventors: Shigetoshi Ito, Takayuki Yuasa, Yoshihiro Ueta, Mototaka Taneya, Zenpei Tani, Kensaku Motoki
  • Publication number: 20130134388
    Abstract: To provide a nitride semiconductor light-emitting element in which a buffer layer provided between an n-type nitride semiconductor layer and a p-type nitride semiconductor layer has a first buffer layer expressed by an equation of Inx1Ga1-x1N (0<x1?1) and a second buffer layer expressed by an equation of Inx2Ga1-x2N (0?x2<1, x2<x1) alternately laminated, an In composition x1 of the first buffer layer is changed, and the In composition x1 of at least one layer of the first buffer layers is higher than an In composition of the active layer, and a method for producing the same.
    Type: Application
    Filed: November 19, 2012
    Publication date: May 30, 2013
    Inventors: Masaya UEDA, Yoshihiro UETA, Yuichi SANO, Toshiyuki OKUMURA
  • Publication number: 20130114633
    Abstract: A nitride semiconductor laser device with a reduction in internal crystal defects and an alleviation in stress, and a semiconductor optical apparatus comprising this nitride semiconductor laser device. First, a growth suppressing film against GaN crystal growth is formed on the surface of an n-type GaN substrate equipped with alternate stripes of dislocation concentrated regions showing a high density of crystal defects and low-dislocation regions so as to coat the dislocation concentrate regions. Next, the n-type GaN substrate coated with the growth suppressing film is overlaid with a nitride semiconductor layer by the epitaxial growth of GaN crystals. Further, the growth suppressing film is removed to adjust the lateral distance between a laser waveguide region and the closest dislocation concentrated region to 40 ?m or more.
    Type: Application
    Filed: November 28, 2012
    Publication date: May 9, 2013
    Inventors: Shigetoshi ITO, Takayuki YUASA, Yoshihiro UETA, Mototaka TANEYA, Zenpei TANI, Kensaku MOTOKI
  • Publication number: 20130037779
    Abstract: A nitride semiconductor light-emitting device includes an n-type nitride semiconductor layer, a V pit generation layer, an intermediate layer, a multiple quantum well light-emitting layer, and a p-type nitride semiconductor layer provided in this order. The multiple quantum well light-emitting layer is a layer formed by alternately stacking a barrier layer and a well layer having a bandgap energy smaller than that of the barrier layer. A V pit is partly formed in the multiple quantum well light-emitting layer, and an average position of starting point of the V pit is located in the intermediate layer.
    Type: Application
    Filed: August 13, 2012
    Publication date: February 14, 2013
    Applicant: Sharp Kabushiki Kaisha
    Inventors: Tadashi Takeoka, Yoshihiko Tani, Kazuya Araki, Yoshihiro Ueta
  • Patent number: 8334544
    Abstract: A nitride semiconductor laser device with a reduction in internal crystal defects and an alleviation in stress, and a semiconductor optical apparatus comprising this nitride semiconductor laser device. First, a growth suppressing film against GaN crystal growth is formed on the surface of an n-type GaN substrate equipped with alternate stripes of dislocation concentrated regions showing a high density of crystal defects and low-dislocation regions so as to coat the dislocation concentrate regions. Next, the n-type GaN substrate coated with the growth suppressing film is overlaid with a nitride semiconductor layer by the epitaxial growth of GaN crystals. Further, the growth suppressing film is removed to adjust the lateral distance between a laser waveguide region and the closest dislocation concentrated region to 40 ?m or more.
    Type: Grant
    Filed: July 14, 2010
    Date of Patent: December 18, 2012
    Assignees: Sharp Kabushiki Kaisha, Sumitomo Electric Industries, Ltd.
    Inventors: Shigetoshi Ito, Takayuki Yuasa, Yoshihiro Ueta, Mototaka Taneya, Zenpei Tani, Kensaku Motoki
  • Publication number: 20120049328
    Abstract: The present invention includes a first step of forming a nitride semiconductor layer by metal organic chemical vapor deposition by using a first carrier gas containing a nitrogen carrier gas and a hydrogen carrier gas of a flow quantity larger than that of the nitrogen carrier gas to thereby supply a raw material containing Mg and a Group V raw material containing N, and a second step of lowering a temperature by using a second carrier gas to which a material containing N is added, and hence solves the problems encountered in the art.
    Type: Application
    Filed: November 4, 2011
    Publication date: March 1, 2012
    Inventors: Yuhzoh Tsuda, Shigetoshi Ito, Mototaka Taneya, Yoshihiro Ueta, Teruyoshi Takakura
  • Publication number: 20120007039
    Abstract: A method of crystal growth is provided which can suppress development of dislocations and cracks and a warp in a substrate. The method of crystal growth of a group III nitride semiconductor has: a step of heating a silicon substrate; and a step of forming a depressed structure on the substrate surface by advance-feeding onto the heated silicon substrate a gas containing at least TMA (trimethylaluminum).
    Type: Application
    Filed: March 3, 2011
    Publication date: January 12, 2012
    Applicants: THE RITSUMEIKAN TRUST, SHARP KABUSHIKI KAISHA
    Inventors: Yoshihiro Ueta, Masataka Ohta, Yoshinobu Aoyagi, Misaichi Takeuchi
  • Patent number: 8076165
    Abstract: The present invention includes a first step of forming a nitride semiconductor layer by metal organic chemical vapor deposition by using a first carrier gas containing a nitrogen carrier gas and a hydrogen carrier gas of a flow quantity larger than that of the nitrogen carrier gas to thereby supply a raw material containing Mg and a Group V raw material containing N, and a second step of lowering a temperature by using a second carrier gas to which a material containing N is added, and hence solves the problems.
    Type: Grant
    Filed: March 2, 2006
    Date of Patent: December 13, 2011
    Assignee: Sharp Kabushiki Kaisha
    Inventors: Yuhzoh Tsuda, Shigetoshi Ito, Mototaka Taneya, Yoshihiro Ueta, Teruyoshi Takakura
  • Patent number: 7858992
    Abstract: A nitride semiconductor laser device has a nitride semiconductor substrate that includes a dislocation-concentrated region 102 and a wide low-dislocation region and that has the top surface thereof slanted at an angle in the range of 0.3° to 0.7° relative to the C plane and a nitride semiconductor layer laid on top thereof. The nitride semiconductor layer has a depression immediately above the dislocation-concentrated region, and has, in a region thereof other than the depression, a high-quality quantum well active layer with good flatness and without cracks, a layer that, as is grown, readily exhibits p-type conductivity, and a stripe-shaped laser light waveguide region. The laser light waveguide region is formed above the low-dislocation region. This helps realize a nitride semiconductor laser device that offers a longer life.
    Type: Grant
    Filed: February 5, 2009
    Date of Patent: December 28, 2010
    Assignees: Sharp Kabushiki Kaisha, Sumitomo Electric Industries, Ltd.
    Inventors: Yoshihiro Ueta, Teruyoshi Takakura, Takeshi Kamikawa, Yuhzoh Tsuda, Shigetoshi Ito, Takayuki Yuasa, Mototaka Taneya, Kensaku Motoki
  • Publication number: 20100278205
    Abstract: A nitride semiconductor laser device with a reduction in internal crystal defects and an alleviation in stress, and a semiconductor optical apparatus comprising this nitride semiconductor laser device. First, a growth suppressing film against GaN crystal growth is formed on the surface of an n-type GaN substrate equipped with alternate stripes of dislocation concentrated regions showing a high density of crystal defects and low-dislocation regions so as to coat the dislocation concentrate regions. Next, the n-type GaN substrate coated with the growth suppressing film is overlaid with a nitride semiconductor layer by the epitaxial growth of GaN crystals. Further, the growth suppressing film is removed to adjust the lateral distance between a laser waveguide region and the closest dislocation concentrated region to 40 ?m or more.
    Type: Application
    Filed: July 14, 2010
    Publication date: November 4, 2010
    Applicants: SHARP KABUSHIKI KAISHA, SUMITOMO ELECTRIC INDUSTRIES, LTD.
    Inventors: Shigetoshi ITO, Takayuki YUASA, Yoshihiro UETA, Mototaka TANEYA, Zenpei TANI, Kensaku MOTOKI
  • Patent number: 7781244
    Abstract: A nitride semiconductor laser device with a reduction in internal crystal defects and an alleviation in stress, and a semiconductor optical apparatus comprising this nitride semiconductor laser device. First, a growth suppressing film against GaN crystal growth is formed on the surface of an n-type GaN substrate equipped with alternate stripes of dislocation concentrated regions showing a high density of crystal defects and low-dislocation regions so as to coat the dislocation concentrate regions. Next, the n-type GaN substrate coated with the growth suppressing film is overlaid with a nitride semiconductor layer by the epitaxial growth of GaN crystals. Further, the growth suppressing film is removed to adjust the lateral distance between a laser waveguide region and the closest dislocation concentrated region to 40 ?m or more.
    Type: Grant
    Filed: September 16, 2008
    Date of Patent: August 24, 2010
    Assignees: Sharp Kabushiki Kaisha, Sumitomo Electric Industries, Ltd.
    Inventors: Shigetoshi Ito, Takayuki Yuasa, Yoshihiro Ueta, Mototaka Taneya, Zenpei Tani, Kensaku Motoki
  • Patent number: 7663158
    Abstract: A nitride compound semiconductor light emitting device includes: a GaN substrate having a crystal orientation which is tilted away from a <0001> direction by an angle which is equal to or greater than about 0.05° and which is equal to or less than about 2°, and a semiconductor multilayer structure formed on the GaN substrate, wherein the semiconductor multilayer structure includes: an acceptor doping layer containing a nitride compound semiconductor; and an active layer including a light emitting region.
    Type: Grant
    Filed: November 16, 2007
    Date of Patent: February 16, 2010
    Assignee: Sharp Kabushiki Kaisha
    Inventors: Yoshihiro Ueta, Takayuki Yuasa, Atsushi Ogawa, Yuhzoh Tsuda, Masahiro Araki
  • Publication number: 20090236585
    Abstract: A nitride semiconductor laser device has a nitride semiconductor substrate that includes a dislocation-concentrated region 102 and a wide low-dislocation region and that has the top surface thereof slanted at an angle in the range of 0.3° to 0.7° relative to the C plane and a nitride semiconductor layer laid on top thereof. The nitride semiconductor layer has a depression immediately above the dislocation-concentrated region, and has, in a region thereof other than the depression, a high-quality quantum well active layer with good flatness and without cracks, a layer that, as is grown, readily exhibits p-type conductivity, and a stripe-shaped laser light waveguide region. The laser light waveguide region is formed above the low-dislocation region. This helps realize a nitride semiconductor laser device that offers a longer life.
    Type: Application
    Filed: February 5, 2009
    Publication date: September 24, 2009
    Applicants: Sharp Kabushiki Kaisha, Sumitomo Electric Industries, Ltd.
    Inventors: Yoshihiro Ueta, Teruyoshi Takakura, Takeshi Kamikawa, Yuhzoh Tsuda, Shigetoshi Ito, Takayuki Yuasa, Mototaka Taneya, Kensaku Motoki
  • Patent number: 7579627
    Abstract: A nitride semiconductor laser device has a nitride semiconductor substrate that includes a dislocation-concentrated region 102 and a wide low-dislocation region and that has the top surface thereof slanted at an angle in the range of 0.3° to 0.7° relative to the C plane and a nitride semiconductor layer laid on top thereof. The nitride semiconductor layer has a depression immediately above the dislocation-concentrated region, and has, in a region thereof other than the depression, a high-quality quantum well active layer with good flatness and without cracks, a layer that, as is grown, readily exhibits p-type conductivity, and a stripe-shaped laser light waveguide region. The laser light waveguide region is formed above the low-dislocation region. This helps realize a nitride semiconductor laser device that offers a longer life.
    Type: Grant
    Filed: May 18, 2006
    Date of Patent: August 25, 2009
    Assignees: Sharp Kabushiki Kaisha, Sumitomo Electric Industries, Ltd.
    Inventors: Yoshihiro Ueta, Teruyoshi Takakura, Takeshi Kamikawa, Yuhzoh Tsuda, Shigetoshi Ito, Takayuki Yuasa, Mototaka Taneya, Kensaku Motoki
  • Publication number: 20090121320
    Abstract: The present invention includes a first step of forming a nitride semiconductor layer by metal organic chemical vapor deposition by using a first carrier gas containing a nitrogen carrier gas and a hydrogen carrier gas of a flow quantity larger than that of the nitrogen carrier gas to thereby supply a raw material containing Mg and a Group V raw material containing N, and a second step of lowering a temperature by using a second carrier gas to which a material containing N is added, and hence solves the problems.
    Type: Application
    Filed: March 2, 2006
    Publication date: May 14, 2009
    Inventors: Yuhzoh Tsuda, Shigetoshi Ito, Mototaka Taneya, Yoshihiro Ueta, Teruyoshi Takakura
  • Patent number: 7515621
    Abstract: A nitride semiconductor laser element includes a lower clad layer, a lower adjacent layer, a quantum well active layer, an upper adjacent layer and an upper clad layer in this order. The quantum well active layer includes a plurality of well layers formed of undoped InGaN, and an undoped barrier layer sandwiched between the well layers. The barrier layer includes a first layer formed of InGaN, a second layer formed of GaN, and a third layer formed of InGaN. The In composition ratio of the first layer and the In composition ratio of the third layer are less than half the In composition ratio of the well layer.
    Type: Grant
    Filed: February 6, 2007
    Date of Patent: April 7, 2009
    Assignee: Sharp Kabushiki Kaisha
    Inventors: Shigetoshi Ito, Yuhzoh Tsuda, Yoshihiro Ueta
  • Patent number: 7498608
    Abstract: A nitride semiconductor laser device with a reduction in internal crystal defects and an alleviation in stress, and a semiconductor optical apparatus comprising this nitride semiconductor laser device. First, a growth suppressing film against GaN crystal growth is formed on the surface of an n-type GaN substrate equipped with alternate stripes of dislocation concentrated regions showing a high density of crystal defects and low-dislocation regions so as to coat the dislocation concentrate regions. Next, the n-type GaN substrate coated with the growth suppressing film is overlaid with a nitride semiconductor layer by the epitaxial growth of GaN crystals. Further, the growth suppressing film is removed to adjust the lateral distance between a laser waveguide region and the closest dislocation concentrated region to 40 ?m or more.
    Type: Grant
    Filed: October 28, 2002
    Date of Patent: March 3, 2009
    Assignees: Sharp Kabushiki Kaisha, Sumitomo Electric Industries, Ltd.
    Inventors: Shigetoshi Ito, Takayuki Yuasa, Yoshihiro Ueta, Mototaka Taneya, Zenpei Tani, Kensaku Motoki