Patents by Inventor Hirokuni Asamizu
Hirokuni Asamizu 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).
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Patent number: 10876220Abstract: A SiC epitaxial wafer includes: a substrate having an off angle of less than 4 degrees; and a SiC epitaxial growth layer disposed on the substrate having the off angle of less than 4 degrees, wherein an Si compound is used for a supply source of Si, and a C compound is used as a supply source of C, for the SiC epitaxial growth layer, wherein the uniformity of carrier density is less than 10%, and the defect density is less than 1 count/cm2; and a C/Si ratio of the Si compound and the C (carbon) compound is within a range of 0.7 to 0.95. There is provide a high-quality SiC epitaxial wafer excellent in film thickness uniformity and uniformity of carrier density, having the small number of surface defects, and capable of reducing costs, also in low-off angle SiC substrates on SiC epitaxial growth.Type: GrantFiled: January 10, 2020Date of Patent: December 29, 2020Assignee: ROHM CO., LTD.Inventor: Hirokuni Asamizu
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Patent number: 10658557Abstract: A transparent light emitting diode (LED) includes a plurality of III-nitride layers, including an active region that emits light, wherein all of the layers except for the active region are transparent for an emission wavelength of the light, such that the light is extracted effectively through all of the layers and in multiple directions through the layers. Moreover, the surface of one or more of the III-nitride layers may be roughened, textured, patterned or shaped to enhance light extraction.Type: GrantFiled: September 12, 2019Date of Patent: May 19, 2020Assignee: THE REGENTS OF THE UNIVERSITY OF CALIFORNIAInventors: Shuji Nakamura, Steven P. DenBaars, Hirokuni Asamizu
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Publication number: 20200149188Abstract: A SiC epitaxial wafer includes: a substrate having an off angle of less than 4 degrees; and a SiC epitaxial growth layer disposed on the substrate having the off angle of less than 4 degrees, wherein an Si compound is used for a supply source of Si, and a C compound is used as a supply source of C, for the SiC epitaxial growth layer, wherein the uniformity of carrier density is less than 10%, and the defect density is less than 1 count/cm2; and a C/Si ratio of the Si compound and the C (carbon) compound is within a range of 0.7 to 0.95. There is provide a high-quality SiC epitaxial wafer excellent in film thickness uniformity and uniformity of carrier density, having the small number of surface defects, and capable of reducing costs, also in low-off angle SiC substrates on SiC epitaxial growth.Type: ApplicationFiled: January 10, 2020Publication date: May 14, 2020Inventor: Hirokuni ASAMIZU
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Patent number: 10644213Abstract: A transparent light emitting diode (LED) includes a plurality of III-nitride layers, including an active region that emits light, wherein all of the layers except for the active region are transparent for an emission wavelength of the light, such that the light is extracted effectively through all of the layers and in multiple directions through the layers. Moreover, the surface of one or more of the III-nitride layers may be roughened, textured, patterned or shaped to enhance light extraction.Type: GrantFiled: September 11, 2019Date of Patent: May 5, 2020Assignee: THE REGENTS OF THE UNIVERSITY OF CALIFORNIAInventors: Shuji Nakamura, Steven P. DenBaars, Hirokuni Asamizu
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Patent number: 10593854Abstract: A transparent light emitting diode (LED) includes a plurality of III-nitride layers, including an active region that emits light, wherein all of the layers except for the active region are transparent for an emission wavelength of the light, such that the light is extracted effectively through all of the layers and in multiple directions through the layers. Moreover, the surface of one or more of the III-nitride layers may be roughened, textured, patterned or shaped to enhance light extraction.Type: GrantFiled: September 13, 2019Date of Patent: March 17, 2020Assignee: The Regents of the University of CaliforniaInventors: Shuji Nakamura, Steven P. DenBaars, Hirokuni Asamizu
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Patent number: 10570529Abstract: A SiC epitaxial wafer includes: a substrate having an off angle of less than 4 degrees; and a SiC epitaxial growth layer disposed on the substrate having the off angle of less than 4 degrees, wherein an Si compound is used for a supply source of Si, and a C compound is used as a supply source of C, for the SiC epitaxial growth layer, wherein the uniformity of carrier density is less than 10%, and the defect density is less than 1 count/cm2; and a C/Si ratio of the Si compound and the C (carbon) compound is within a range of 0.7 to 0.95. There is provide a high-quality SiC epitaxial wafer excellent in film thickness uniformity and uniformity of carrier density, having the small number of surface defects, and capable of reducing costs, also in low-off angle SiC substrates on SiC epitaxial growth.Type: GrantFiled: April 29, 2019Date of Patent: February 25, 2020Assignee: ROHM CO., LTD.Inventor: Hirokuni Asamizu
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Patent number: 10454010Abstract: A transparent light emitting diode (LED) includes a plurality of III-nitride layers, including an active region that emits light, wherein all of the layers except for the active region are transparent for an emission wavelength of the light, such that the light is extracted effectively through all of the layers and in multiple directions through the layers. Moreover, the surface of one or more of the III-nitride layers may be roughened, textured, patterned or shaped to enhance light extraction.Type: GrantFiled: May 24, 2019Date of Patent: October 22, 2019Assignee: THE REGENTS OF THE UNIVERSITY OF CALIFORNIAInventors: Shuji Nakamura, Steven P. DenBaars, Hirokuni Asamizu
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Publication number: 20190273194Abstract: A transparent light emitting diode (LED) includes a plurality of III-nitride layers, including an active region that emits light, wherein all of the layers except for the active region are transparent for an emission wavelength of the light, such that the light is extracted effectively through all of the layers and in multiple directions through the layers. Moreover, the surface of one or more of the III-nitride layers may be roughened, textured, patterned or shaped to enhance light extraction.Type: ApplicationFiled: January 3, 2019Publication date: September 5, 2019Applicant: The Regents of the University of CaliforniaInventors: Shuji Nakamura, Steven P. DenBaars, Hirokuni Asamizu
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Publication number: 20190257001Abstract: A SiC epitaxial wafer includes: a substrate having an off angle of less than 4 degrees; and a SiC epitaxial growth layer disposed on the substrate having the off angle of less than 4 degrees, wherein an Si compound is used for a supply source of Si, and a C compound is used as a supply source of C, for the SiC epitaxial growth layer, wherein the uniformity of carrier density is less than 10%, and the defect density is less than 1 count/cm2; and a C/Si ratio of the Si compound and the C (carbon) compound is within a range of 0.7 to 0.95. There is provide a high-quality SiC epitaxial wafer excellent in film thickness uniformity and uniformity of carrier density, having the small number of surface defects, and capable of reducing costs, also in low-off angle SiC substrates on SiC epitaxial growth.Type: ApplicationFiled: April 29, 2019Publication date: August 22, 2019Inventor: Hirokuni ASAMIZU
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Patent number: 10323335Abstract: A SiC epitaxial wafer includes: a substrate having an off angle of less than 4 degrees; and a SiC epitaxial growth layer disposed on the substrate having the off angle of less than 4 degrees, wherein an Si compound is used for a supply source of Si, and a C compound is used as a supply source of C, for the SiC epitaxial growth layer, wherein the uniformity of carrier density is less than 10%, and the defect density is less than 1 count/cm2; and a C/Si ratio of the Si compound and the C (carbon) compound is within a range of 0.7 to 0.95. There is provide a high-quality SiC epitaxial wafer excellent in film thickness uniformity and uniformity of carrier density, having the small number of surface defects, and capable of reducing costs, also in low-off angle SiC substrates on SiC epitaxial growth.Type: GrantFiled: March 12, 2018Date of Patent: June 18, 2019Assignee: ROHM CO., LTD.Inventor: Hirokuni Asamizu
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Patent number: 10217916Abstract: A transparent light emitting diode (LED) includes a plurality of III-nitride layers, including an active region that emits light, wherein all of the layers except for the active region are transparent for an emission wavelength of the light, such that the light is extracted effectively through all of the layers and in multiple directions through the layers. Moreover, the surface of one or more of the III-nitride layers may be roughened, textured, patterned or shaped to enhance light extraction.Type: GrantFiled: August 15, 2014Date of Patent: February 26, 2019Assignee: THE REGENTS OF THE UNIVERSITY OF CALIFORNIAInventors: Shuji Nakamura, Steven P. DenBaars, Hirokuni Asamizu
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Publication number: 20180202070Abstract: A SiC epitaxial wafer includes: a substrate having an off angle of less than 4 degrees; and a SiC epitaxial growth layer disposed on the substrate having the off angle of less than 4 degrees, wherein an Si compound is used for a supply source of Si, and a C compound is used as a supply source of C, for the SiC epitaxial growth layer, wherein the uniformity of carrier density is less than 10%, and the defect density is less than 1 count/cm2; and a C/Si ratio of the Si compound and the C (carbon) compound is within a range of 0.7 to 0.95. There is provide a high-quality SiC epitaxial wafer excellent in film thickness uniformity and uniformity of carrier density, having the small number of surface defects, and capable of reducing costs, also in low-off angle SiC substrates on SiC epitaxial growth.Type: ApplicationFiled: March 12, 2018Publication date: July 19, 2018Inventor: Hirokuni ASAMIZU
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Publication number: 20160064488Abstract: A nitride based semiconductor device includes: a substrate; a first buffer layer disposed on the substrate; a second buffer layer disposed on the first buffer layer; a third buffer layer disposed on the second buffer layer, the third buffer layer including an AlGaN-based nitride semiconductor; a fourth buffer layer disposed on the third buffer layer, the fourth buffer layer including a GaN-based nitride semiconductor; a barrier layer disposed on the fourth buffer layer, the barrier layer including an AlGaN-based nitride semiconductor; and a source electrode and a drain electrode, each disposed on the barrier layer, and a gate electrode disposed between the source electrode and the drain electrode, wherein the third buffer layer is subjected to lattice relaxation. There can be provided a nitride based semiconductor device capable of reducing a leakage current and improving breakdown capability.Type: ApplicationFiled: November 6, 2015Publication date: March 3, 2016Applicant: ROHM CO., LTD.Inventors: Shinya TAKADO, Norikazu ITO, Junichi KASHIWAGI, Hirokuni ASAMIZU
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Publication number: 20140353707Abstract: A transparent light emitting diode (LED) includes a plurality of III-nitride layers, including an active region that emits light, wherein all of the layers except for the active region are transparent for an emission wavelength of the light, such that the light is extracted effectively through all of the layers and in multiple directions through the layers. Moreover, the surface of one or more of the III-nitride layers may be roughened, textured, patterned or shaped to enhance light extraction.Type: ApplicationFiled: August 15, 2014Publication date: December 4, 2014Applicant: THE REGENTS OF THE UNIVERSITY OF CALIFORNIAInventors: Shuji Nakamura, Steven P. DenBaars, Hirokuni Asamizu
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Patent number: 8835959Abstract: A transparent light emitting diode (LED) includes a plurality of III-nitride layers, including an active region that emits light, wherein all of the layers except for the active region are transparent for an emission wavelength of the light, such that the light is extracted effectively through all of the layers and in multiple directions through the layers. Moreover, the surface of one or more of the III-nitride layers may be roughened, textured, patterned or shaped to enhance light extraction.Type: GrantFiled: September 19, 2012Date of Patent: September 16, 2014Assignee: The Regents of the University of CaliforniaInventors: Shuji Nakamura, Steven P. DenBaars, Hirokuni Asamizu
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Publication number: 20140191244Abstract: A method of controlled p-type conductivity in (Al,In,Ga,B)N semiconductor crystals. Examples include {10 11} GaN films deposited on {100} MgAl2O4 spinel substrate miscut in the <011> direction. Mg atoms may be intentionally incorporated in the growing semipolar nitride thin film to introduce available electronic states in the band structure of the semiconductor crystal, resulting in p-type conductivity. Other impurity atoms, such as Zn or C, which result in a similar introduction of suitable electronic states, may also be used.Type: ApplicationFiled: March 12, 2014Publication date: July 10, 2014Applicant: THE REGENTS OF THE UNIVERSITY OF CALIFORNIAInventors: John F. Kaeding, Hitoshi Sato, Michael Iza, Hirokuni Asamizu, Hong Zhong, Steven P. DenBaars, Shuji Nakamura
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Patent number: 8709925Abstract: A method of controlled p-type conductivity in (Al,In,Ga,B)N semiconductor crystals. Examples include {10 11} GaN films deposited on {100} MgAl2O4 spinel substrate miscut in the <011> direction. Mg atoms may be intentionally incorporated in the growing semipolar nitride thin film to introduce available electronic states in the band structure of the semiconductor crystal, resulting in p-type conductivity. Other impurity atoms, such as Zn or C, which result in a similar introduction of suitable electronic states, may also be used.Type: GrantFiled: April 5, 2012Date of Patent: April 29, 2014Assignee: The Regents of the University of CaliforniaInventors: John F. Kaeding, Hitoshi Sato, Michael Iza, Hirokuni Asamizu, Hong Zhong, Steven P. DenBaars, Shuji Nakamura
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Patent number: 8368109Abstract: An (Al,Ga,In)N-based light emitting diode (LED), comprising a p-type surface of the LED bonded with a transparent submount material to increase light extraction at the p-type surface, wherein the LED is a substrateless membrane.Type: GrantFiled: November 15, 2011Date of Patent: February 5, 2013Assignee: The Regents of the University of CaliforniaInventors: Kenji Iso, Hirokuni Asamizu, Makoto Saito, Hitoshi Sato, Steven P. DenBaars, Shuji Nakamura
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Patent number: 8294166Abstract: A transparent light emitting diode (LED) includes a plurality of III-nitride layers, including an active region that emits light, wherein all of the layers except for the active region are transparent for an emission wavelength of the light, such that the light is extracted effectively through all of the layers and in multiple directions through the layers. Moreover, the surface of one or more of the III-nitride layers may be roughened, textured, patterned or shaped to enhance light extraction.Type: GrantFiled: December 11, 2007Date of Patent: October 23, 2012Assignee: The Regents of the University of CaliforniaInventors: Shuji Nakamura, Steven P. DenBaars, Hirokuni Asamizu
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Publication number: 20120187415Abstract: A method of controlled p-type conductivity in (Al,In,Ga,B)N semiconductor crystals. Examples include {10 11} GaN films deposited on {100} MgAl2O4 spinel substrate miscut in the <011> direction. Mg atoms may be intentionally incorporated in the growing semipolar nitride thin film to introduce available electronic states in the band structure of the semiconductor crystal, resulting in p-type conductivity. Other impurity atoms, such as Zn or C, which result in a similar introduction of suitable electronic states, may also be used.Type: ApplicationFiled: April 5, 2012Publication date: July 26, 2012Applicant: THE REGENTS OF THE UNIVERSITY OF CALIFORNIAInventors: John F. Kaeding, Hitoshi Sato, Michael Iza, Hirokuni Asamizu, Hong Zhong, Steven P. DenBaars, Shuji Nakamura