Patents by Inventor Yuhzoh Tsuda

Yuhzoh Tsuda 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: 6924512
    Abstract: A nitride semiconductor light emitting device includes an emission layer (106) having a multiple quantum well structure where a plurality of quantum well layers and a plurality of barrier layers are alternately stacked. The quantum well layer is formed of XN1-x-y-zAsxPySbz (0?x?0.15, 0?y?0.2, 0?z?0.05, x+y+z>0) where X represents one or more kinds of group III elements. The barrier layer is formed of a nitride semiconductor layer containing at least Al.
    Type: Grant
    Filed: May 7, 2001
    Date of Patent: August 2, 2005
    Assignee: Sharp Kabushiki Kaisha
    Inventors: Yuhzoh Tsuda, Takayuki Yuasa, Shigetoshi Ito
  • Publication number: 20050141577
    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: April 26, 2004
    Publication date: June 30, 2005
    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: 6909120
    Abstract: According to an aspect of the present invention, a nitride semiconductor light emitting device includes a light emitting layer having a quantum well structure with quantum well layers and barrier layers laminated alternately. The well layer is formed of a nitride semiconductor containing In, and the barrier layer is formed of a nitride semiconductor layer containing As, P or Sb. According to another aspect of the present invention, a nitride semiconductor light emitting device includes a light emitting layer having a quantum well structure with quantum well layers and barrier layers laminated alternately. The well layer is formed of GaN1?x?y?zAsxPySbz (0<x+y+z?0.3), and the barrier layer is formed of a nitride semiconductor containing In.
    Type: Grant
    Filed: November 5, 2001
    Date of Patent: June 21, 2005
    Assignee: Sharp Kabushiki Kaisha
    Inventors: Yuhzoh Tsuda, Shigetoshi Ito
  • Patent number: 6891189
    Abstract: A nitride semiconductor laser device includes a nitride semiconductor substrate, and a layered portion corresponding to a nitride semiconductor film grown on the nitride semiconductor substrate, the layered portion including an n-type layer and a p-type layer and a light emitting layer posed between the n- and p-type layers, of the n- and p-type layers a layer opposite to the nitride semiconductor substrate with the light emitting layer opposed therebetween serving as an upper layer having a stripe of 1.9 ?m to 3.0 ?n in width, the light emitting layer and the upper layer having an interface distant from a bottom of the stripe by 0 ?m to 0.2 ?m.
    Type: Grant
    Filed: July 9, 2003
    Date of Patent: May 10, 2005
    Assignee: Sharp Kabushiki Kaisha
    Inventors: Shigetoshi Ito, Yuhzoh Tsuda
  • Patent number: 6891201
    Abstract: A nitride semiconductor light emitting device includes a processed substrate (101a) including a groove and a hill formed on a main surface of a nitride semiconductor substrate, a nitride semiconductor underlayer (102) covering the groove and the hill of the processed substrate, and a light emitting device structure having a light emitting layer (106) including a quantum well layer or a quantum well layer and a barrier layer in contact with the quantum well layer between an n type layer (103-105) and a p type layer (107-110) over the nitride semiconductor underlayer. A current-constricting portion of the light emitting device structure is formed above a region more than 1 ?m away from the center of the groove in the width direction and more than 1 ?m away from the center of the hill in the width direction.
    Type: Grant
    Filed: January 9, 2002
    Date of Patent: May 10, 2005
    Assignee: Sharp Kabushiki Kaisha
    Inventors: Yuhzoh Tsuda, Takayuki Yuasa, Shigetoshi Ito, Mototaka Taneya, Yukio Yamasaki
  • Publication number: 20050095768
    Abstract: According to an aspect of the present invention, a nitride semiconductor light emitting device includes a light emitting layer having a quantum well structure with quantum well layers and barrier layers laminated alternately. The well layer is formed of a nitride semiconductor containing In, and the barrier layer is formed of a nitride semiconductor layer containing As, P or Sb. According to another aspect of the present invention, a nitride semiconductor light emitting device includes a light emitting layer having a quantum well structure with quantum well layers and barrier layers laminated alternately. The well layer is formed of GaN1-x-y-zAsxPySbz (0<x+y+z?0.3), and the barrier layer is formed of a nitride semiconductor containing In.
    Type: Application
    Filed: November 5, 2001
    Publication date: May 5, 2005
    Inventors: Yuhzoh Tsuda, Shigetoshi Ito
  • Patent number: 6881981
    Abstract: In a nitride semiconductor light emitting device chip, a mask pattern on a nitride semiconductor substrate (101) is formed of a growth inhibiting film on which a nitride semiconductor layer is hard to grow. There are a plurality of windows unprovided with the growth inhibiting film. There are at least two different widths as mask widths each between the adjacent windows. The mask pattern includes a mask A group (MAG) and mask B groups (MBG) arranged on respective sides of the mask A group. A mask A width in the mask A group is wider than a mask B width in the mask B group. The nitride semiconductor light emitting device chip further includes a nitride semiconductor underlayer (102) covering the windows and the mask pattern, and a light emitting device structure having a light emitting layer (106) including at least one quantum well layer between an n type layer (103-105) and a p type layer (107-110) over the underlayer.
    Type: Grant
    Filed: December 27, 2001
    Date of Patent: April 19, 2005
    Assignee: Sharp Kabushiki Kaisha
    Inventors: Yuhzoh Tsuda, Shigetoshi Ito
  • Patent number: 6858882
    Abstract: A nitride semiconductor light-emitting device includes an emission layer (103) formed on a substrate (100), and the emission layer includes a quantum well layer of GaN1-x?y?zAsxPySbz (0<x+y+z?0.3) containing Al.
    Type: Grant
    Filed: September 4, 2001
    Date of Patent: February 22, 2005
    Assignee: Sharp Kabushiki Kaisha
    Inventors: Yuhzoh Tsuda, Shigetoshi Ito, Kouichi Morishige
  • Patent number: 6815728
    Abstract: A light-emitting device has a light-emitting layer of nitride semiconductor containing As, P or Sb and accordingly its emission efficiency or emission intensity is enhanced. The light-emitting device includes a substrate, and further includes n-type and p-type nitride semiconductor layers and a light-emitting layer between the n-type and p-type semiconductor layers that are formed on the substrate. Light-emitting layer includes one or a plurality of well layers formed of nitride semiconductor containing N and element X (element X is As, P or Sb). The nitride semiconductor of the well layer has at most 30% in atomic percent represented by expression {NX/(NN+NX)}×100 where NX represents the number of atoms of element X and NN represents the number of atoms of N. The thickness of the well layer ranges from 0.4 nm to 4.8 nm.
    Type: Grant
    Filed: April 19, 2002
    Date of Patent: November 9, 2004
    Assignee: Sharp Kabushiki Kaisha
    Inventors: Yuhzoh Tsuda, Shigetoshi Ito
  • Patent number: 6765233
    Abstract: A method for producing a semiconductor substrate of the present invention, includes the steps: forming a first patterned mask containing a material having a growth suppressing effect on a lower substrate; growing a semiconductor crystal on the lower substrate via the first patterned mask to form a first semiconductor crystal layer; forming a second patterned mask containing a material having a growth suppressing effect on or above the lower substrate, the second patterned mask at least having a surface which is positioned at a level different from a level of a surface of the first patterned mask, with respect to a surface of the lower substrate; and growing a semiconductor crystal on or above the lower substrate via the second patterned mask to form a second semiconductor crystal layer.
    Type: Grant
    Filed: July 11, 2001
    Date of Patent: July 20, 2004
    Assignee: Sharp Kabushiki Kaisha
    Inventors: Yuhzoh Tsuda, Shigetoshi Ito, Seiki Yano
  • Publication number: 20040056261
    Abstract: In a nitride semiconductor light emitting device chip, a mask pattern on a nitride semiconductor substrate (101) is formed of a growth inhibiting film on which a nitride semiconductor layer is hard to grow. There are a plurality of windows unprovided with the growth inhibiting film. There are at least two different widths as mask widths each between the adjacent windows. The mask pattern includes a mask A group (MAG) and mask B groups (MBG) arranged on respective sides of the mask A group. A mask A width in the mask A group is wider than a mask B width in the mask B group. The nitride semiconductor light emitting device chip further includes a nitride semiconductor underlayer (102) covering the windows and the mask pattern, and a light emitting device structure having a light emitting layer (106) including at least one quantum well layer between an n type layer (103-105) and a p type layer (107-110) over the underlayer.
    Type: Application
    Filed: July 3, 2003
    Publication date: March 25, 2004
    Inventors: Yuhzoh Tsuda, Shigetoshi Ito
  • Publication number: 20040051105
    Abstract: A nitride semiconductor light-emitting device includes an emission layer (103) formed on a substrate (100), and the emission layer includes a quantum well layer of GaN1−x-y−zAsxPySbz (0<x+y+z≦0.3) containing Al.
    Type: Application
    Filed: August 1, 2003
    Publication date: March 18, 2004
    Inventors: Yuhzoh Tsuda, Shigetoshi Ito, Kouichi Morishige
  • Publication number: 20040041156
    Abstract: The nitride semiconductor light emitting device includes a nitride semiconductor underlayer (102) grown on a surface of a nitride semiconductor substrate or a surface of a nitride semiconductor substrate layer laminated over a base substrate of other than a nitride semiconductor, and a light emitting device structure having a light emitting layer (106) including a quantum well layer or a quantum well layer and a barrier layer in contact with the quantum well layer between an n type layer (103-105) and a p type layer (107-110) over the nitride semiconductor underlayer. It includes a depression (D) not flattened on a surface of the light emitting device structure even after growth of the light emitting device structure.
    Type: Application
    Filed: August 14, 2003
    Publication date: March 4, 2004
    Inventors: Yuhzoh Tsuda, Daisuke Hanaoka, Takayuki Yuasa, Shigetoshi Ito, Motokata Taneya
  • Publication number: 20040026710
    Abstract: According to an aspect of the present invention, a nitride semiconductor light emitting device includes a light emitting layer (106) having a quantum well structure with quantum well layers and barrier layers laminated alternately. The well layer is formed of a nitride semiconductor containing In, and the barrier layer is formed of a nitride semiconductor layer containing As, P or Sb. According to another aspect of the present invention, a nitride semiconductor light emitting device includes a light emitting layer having a quantum well structure with quantum well layers and barrier layers laminated alternately. The well layer is formed of GaN1-x-y-zAsxPySbz (0<x+y+z≦0.3), and the barrier layer is formed of a nitride semiconductor containing In.
    Type: Application
    Filed: March 20, 2003
    Publication date: February 12, 2004
    Inventors: Yuhzoh Tsuda, Shigetoshi Ito, Masahiro Araki
  • Publication number: 20040026685
    Abstract: A nitride semiconductor laser device includes a nitride semiconductor substrate, and a layered portion corresponding to a nitride semiconductor film grown on the nitride semiconductor substrate, the layered portion including an n-type layer and a p-type layer and a light emitting layer posed between the n- and p-type layers, of the n- and p-type layers a layer opposite to the nitride semiconductor substrate with the light emitting layer opposed therebetween serving as an upper layer having a stripe of 1.9 &mgr;m to 3.0 &mgr;n in width, the light emitting layer and the upper layer having an interface distant from a bottom of the stripe by 0 &mgr;m to 0.2 &mgr;m.
    Type: Application
    Filed: July 9, 2003
    Publication date: February 12, 2004
    Inventors: Shigetoshi Ito, Yuhzoh Tsuda
  • Patent number: 6620238
    Abstract: A nitride semiconductor structure includes: a substrate having a growth surface, a convex portion and a concave portion being formed on the growth surface; and a nitride semiconductor film grown on the growth surface. A cavity is formed between the nitride semiconductor film and the substrate in the concave portion.
    Type: Grant
    Filed: October 2, 2001
    Date of Patent: September 16, 2003
    Assignee: Sharp Kabushiki Kaisha
    Inventors: Yuhzoh Tsuda, Takayuki Yuasa
  • Patent number: 6617607
    Abstract: A nitride semiconductor laser device includes a nitride semiconductor substrate, and a layered portion corresponding to a nitride semiconductor film grown on the nitride semiconductor substrate, the layered portion including an n-type layer and a p-type layer and a light emitting layer posed between the n- and p-type layers, of the n- and p-type layers a layer opposite to the nitride semiconductor substrate with the light emitting layer opposed therebetween serving as an upper layer having a stripe of 1.9 &mgr;m to 3.0 &mgr;m in width, the light emitting layer and the upper layer having an interface distant from a bottom of the stripe by 0 &mgr;m to 0.2 &mgr;m.
    Type: Grant
    Filed: April 26, 2001
    Date of Patent: September 9, 2003
    Assignee: Sharp Kabushiki Kaisha
    Inventors: Shigetoshi Ito, Yuhzoh Tsuda
  • Patent number: 6614824
    Abstract: A nitride semiconductor laser device having a low threshold current and low noise is provided. The laser device includes n-type and p-type layers made of nitride semiconductor and formed on a substrate, and a light emitting layer between the n-type and p-type layers. The light emitting layer is formed of a well layer or a combination of well and barrier layers. At least the well layer is made of nitride semiconductor containing element X, N and Ga, wherein element is at least one selected from the group consisting of As, P and Sb. The atomic fraction of element X is smaller than that of N. A maximum width through which current is injected into the light emitting layer via the p-type layer is from 1.0 &mgr;m to 4.0 &mgr;m.
    Type: Grant
    Filed: September 13, 2001
    Date of Patent: September 2, 2003
    Assignee: Sharp Kabushiki Kaisha
    Inventors: Yuhzoh Tsuda, Shigetoshi Ito, Toshiyuki Okumura
  • Publication number: 20030136957
    Abstract: A nitride semiconductor light emitting device includes an emission layer (106) having a multiple quantum well structure where a plurality of quantum well layers and a plurality of barrier layers are alternately stacked. The quantum well layer is formed of XN1-x-yAsxPySbz (0≦x≦0.15, 0≦y≦0.2, 0≦z≦0.05, x+y+z>0) where X represents one or more kinds of group III elements. The barrier layer is formed of a nitride semiconductor layer containing at least Al.
    Type: Application
    Filed: November 14, 2002
    Publication date: July 24, 2003
    Inventors: Yuhzoh Tsuda, Takayuki Yuasa, Shigetoshi Ito
  • Patent number: 6586316
    Abstract: A method for producing a semiconductor substrate includes the steps of: forming a first patterned mask containing a material having a growth suppressing effect on a substrate; growing a first nitride semiconductor on a portion of the substrate corresponding to an opening portion of the first patterned mask; forming a second patterned mask containing a material having a growth suppressing effect only on a main surface of the first nitride semiconductor which is positioned above the opening portion of the first patterned mask; and growing a semiconductor crystal substantially from the side surface of the first nitride semiconductor so as to form a second nitride semiconductor which integrally includes the first patterned mask and the second patterned mask.
    Type: Grant
    Filed: March 1, 2002
    Date of Patent: July 1, 2003
    Assignee: Sharp Kabushiki Kaisha
    Inventors: Yuhzoh Tsuda, Shingetoshi Ito, Seiki Yano