Patents by Inventor Steven P. Denbaars

Steven P. Denbaars 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: 8334151
    Abstract: An (Al, Ga, In)N and ZnO direct wafer bonded light emitting diode (LED), wherein light passes through electrically conductive ZnO. Flat and clean surfaces are prepared for both the (Al, Ga, In)N and ZnO wafers. A wafer bonding process is then performed between the (Al, Ga, In)N and ZnO wafers, wherein the (Al, Ga, In)N and ZnO wafers are joined together and then wafer bonded in a nitrogen ambient under uniaxial pressure at a set temperature for a set duration. After the wafer bonding process, ZnO is shaped for increasing light extraction from inside of LED.
    Type: Grant
    Filed: April 1, 2010
    Date of Patent: December 18, 2012
    Assignee: The Regents of the University of California
    Inventors: Akihiko Murai, Christina Ye Chen, Daniel B. Thompson, Lee S. McCarthy, Steven P. DenBaars, Shuji Nakamura, Umesh K. Mishra
  • Publication number: 20120313076
    Abstract: A light emitting diode structure of (Al,Ga,In)N thin films grown on a gallium nitride (GaN) semipolar substrate by metal organic chemical vapor deposition (MOCVD) that exhibits reduced droop. The device structure includes a quantum well (QW) active region of two or more periods, n-type superlattice layers (n-SLs) located below the QW active region, and p-type superlattice layers (p-SLs) above the QW active region. The present invention also encompasses a method of fabricating such a device.
    Type: Application
    Filed: June 11, 2012
    Publication date: December 13, 2012
    Applicant: The Regents of the University of California
    Inventors: Shuji Nakamura, Steven P. DenBaars, Shinichi Tanaka, Daniel F. Feezell, Yuji Zhao, Chih-Chien Pan
  • Publication number: 20120313077
    Abstract: High emission power and low efficiency droop semipolar blue light emitting diodes (LEDs).
    Type: Application
    Filed: June 11, 2012
    Publication date: December 13, 2012
    Applicant: The Regents of the University of California
    Inventors: Shuji Nakamura, Steven P. DenBaars, Daniel F. Feezell, Chih-Chien Pan, Yuji Zhao, Shinichi Tanaka
  • Publication number: 20120286241
    Abstract: A method for fabricating a III-nitride based semiconductor device, including (a) growing one or more buffer layers on or above a semi-polar or non-polar GaN substrate, wherein the buffer layers are semi-polar or non-polar III-nitride buffer layers; and (b) doping the buffer layers so that a number of crystal defects in III-nitride device layers formed on or above the doped buffer layers is not higher than a number of crystal defects in III-nitride device layers formed on or above one or more undoped buffer layers. The doping can reduce or prevent formation of misfit dislocation lines and additional threading dislocations. The thickness and/or composition of the buffer layers can be such that the buffer layers have a thickness near or greater than their critical thickness for relaxation. In addition, one or more (AlInGaN) or III-nitride device layers can be formed on or above the buffer layers.
    Type: Application
    Filed: May 14, 2012
    Publication date: November 15, 2012
    Applicant: THE REGENTS OF THE UNIVERSITY OF CALIFORNIA
    Inventors: Matthew T. Hardy, Po Shan Hsu, Steven P. DenBaars, James S. SPECK, Shuji Nakamura
  • Publication number: 20120273796
    Abstract: A Group-III nitride optoelectronic device fabricated on a semipolar (20-2-1) plane of a Gallium Nitride (GaN) substrate is characterized by a high Indium uptake and a high polarization ratio.
    Type: Application
    Filed: April 30, 2012
    Publication date: November 1, 2012
    Applicant: THE REGENTS OF THE UNIVERSITY OF CALIFORNIA
    Inventors: Yuji Zhao, Shinichi Tanaka, Chia-Yen Huang, Daniel F. Feezell, James S. Speck, Steven P. DenBaars, Shuji Nakamura
  • Patent number: 8299452
    Abstract: A yellow Light Emitting Diode (LED) with a peak emission wavelength in the range 560-580 nm is disclosed. The LED is grown on one or more III-nitride-based semipolar planes and an active layer of the LED is composed of indium (In) containing single or multi-quantum well structures. The LED quantum wells have a thickness in the range 2-7 nm. A multi-color LED or white LED comprised of at least one semipolar yellow LED is also disclosed.
    Type: Grant
    Filed: February 27, 2012
    Date of Patent: October 30, 2012
    Assignee: The Regents of the University of California
    Inventors: Hitoshi Sato, Hirohiko Hirasawa, Roy B. Chung, Steven P. DenBaars, James S. Speck, Shuji Nakamura
  • Patent number: 8294166
    Abstract: 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: Grant
    Filed: December 11, 2007
    Date of Patent: October 23, 2012
    Assignee: The Regents of the University of California
    Inventors: Shuji Nakamura, Steven P. DenBaars, Hirokuni Asamizu
  • Publication number: 20120256158
    Abstract: A method for fabricating AlxGa1-xN-cladding-free nonpolar III-nitride based laser diodes or light emitting diodes. Due to the absence of polarization fields in the nonpolar crystal planes, these nonpolar devices have thick quantum wells that function as an optical waveguide to effectively confine the optical mode to the active region and eliminate the need for Al-containing waveguide cladding layers.
    Type: Application
    Filed: June 13, 2012
    Publication date: October 11, 2012
    Applicant: THE REGENTS OF THE UNIVERSITY OF CALIFORNIA
    Inventors: Daniel F. Feezell, Mathew C. Schmidt, Kwang Choong Kim, Robert M. Farrell, Daniel A. Cohen, James S. Speck, Steven P. DenBaars, Shuji Nakamura
  • Patent number: 8278128
    Abstract: An off-axis cut of a nonpolar III-nitride wafer towards a polar (?c) orientation results in higher polarization ratios for light emission than wafers without such off-axis cuts. A 5° angle for an off-axis cut has been confirmed to provide the highest polarization ratio (0.9) than any other examined angles for off-axis cuts between 0° and 27°.
    Type: Grant
    Filed: February 2, 2009
    Date of Patent: October 2, 2012
    Assignee: The Regents of the University of California
    Inventors: Hisashi Masui, Hisashi Yamada, Kenji Iso, Asako Hirai, Makoto Saito, James S. Speck, Shuji Nakamura, Steven P. DenBaars
  • Patent number: 8263500
    Abstract: A method for fabricating a semiconductor laser device, by etching facets using a photoelectrochemical (PEC) etch, so that the facets are sufficiently smooth to support optical modes within a cavity bounded by the facets.
    Type: Grant
    Filed: February 1, 2010
    Date of Patent: September 11, 2012
    Assignee: The Regents of the University of California
    Inventors: Adele C. Tamboli, Evelyn L. Hu, Steven P. DenBaars, Arpan Chakraborty
  • Patent number: 8254423
    Abstract: A method of fabricating an (Al,Ga,In)N laser diode, comprising depositing one or more III-N layers upon a growth substrate at a first temperature, depositing an indium containing laser core at a second temperature upon layers deposited at a first temperature, and performing all subsequent fabrication steps under conditions that inhibit degradation of the laser core, wherein the conditions are a substantially lower temperature than the second temperature.
    Type: Grant
    Filed: June 1, 2009
    Date of Patent: August 28, 2012
    Assignee: The Regents of the University of California
    Inventors: Daniel A. Cohen, Steven P. DenBaars, Shuji Nakamura
  • Publication number: 20120205623
    Abstract: A method for forming non-polar (Al,B,In,Ga)N quantum well and heterostructure materials and devices. Non-polar (11 20) a-plane GaN layers are grown on an r-plane (11 02) sapphire substrate using MOCVD. These non-polar (11 20) a-plane GaN layers comprise templates for producing non-polar (Al,B,In,Ga)N quantum well and heterostructure materials and devices.
    Type: Application
    Filed: April 26, 2012
    Publication date: August 16, 2012
    Applicant: THE REGENTS OF THE UNIVERSITY OF CALIFORNIA
    Inventors: Michael D. Craven, Stacia Keller, Steven P. DenBaars, Tal Margalith, James Stephen Speck, Shuji Nakamura, Umesh K. Mishra
  • Publication number: 20120205625
    Abstract: A nitride light emitting diode, on a patterned substrate, comprising a nitride interlayer having at least two periods of alternating layers of InxGa1-xN and InyGa1-yN where 0<x<1 and 0?y<1, and a nitride based active region having at least one quantum well structure on the nitride interlayer.
    Type: Application
    Filed: April 24, 2012
    Publication date: August 16, 2012
    Applicant: THE REGENTS OF THE UNIVERSITY OF CALIFORNIA
    Inventors: Michael Iza, Hitoshi Sato, Eu Jin Hwang, Steven P. DenBaars, Shuji Nakamura
  • Publication number: 20120205620
    Abstract: A yellow Light Emitting Diode (LED) with a peak emission wavelength in the range 560-580 nm is disclosed. The LED is grown on one or more III-nitride-based semipolar planes and an active layer of the LED is composed of indium (In) containing single or multi-quantum well structures. The LED quantum wells have a thickness in the range 2-7 nm. A multi-color LED or white LED comprised of at least one semipolar yellow LED is also disclosed.
    Type: Application
    Filed: February 27, 2012
    Publication date: August 16, 2012
    Applicant: THE REGENTS OF THE UNIVERSITY OF CALIFORNIA
    Inventors: Hitoshi Sato, Hirohiko Hirasawa, Roy B. Chung, Steven P. DenBaars, James S. Speck, Shuji Nakamura
  • Publication number: 20120199809
    Abstract: A method of device growth and p-contact processing that produces improved performance for non-polar III-nitride light emitting diodes and laser diodes. Key components using a low defect density substrate or template, thick quantum wells, a low temperature p-type III-nitride growth technique, and a transparent conducting oxide for the electrodes.
    Type: Application
    Filed: April 5, 2012
    Publication date: August 9, 2012
    Applicants: JAPAN SCIENCE AND TECHNOLOGY AGENCY, THE REGENTS OF THE UNIVERSITY OF CALIFORNIA
    Inventors: Mathew C. Schmidt, Kwang Choong Kim, Hitoshi Sato, Steven P. DenBaars, James S. Speck, Shuji Nakamura
  • Publication number: 20120187415
    Abstract: 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: Application
    Filed: April 5, 2012
    Publication date: July 26, 2012
    Applicant: THE REGENTS OF THE UNIVERSITY OF CALIFORNIA
    Inventors: John F. Kaeding, Hitoshi Sato, Michael Iza, Hirokuni Asamizu, Hong Zhong, Steven P. DenBaars, Shuji Nakamura
  • Patent number: 8227819
    Abstract: A light emitting diode (LED) having a p-type layer having a thickness of 100 nm or less, an n-type layer, and an active layer, positioned between the p-type layer and the n-type layer, for emitting light, wherein the LED does not include a separate electron blocking layer.
    Type: Grant
    Filed: September 30, 2011
    Date of Patent: July 24, 2012
    Assignee: The Regents of the University of California
    Inventors: Hong Zhong, Anurag Tyagi, James Stephen Speck, Steven P. Denbaars, Shuji Nakamura
  • Publication number: 20120180868
    Abstract: A III-nitride photovoltaic device structure and method for fabricating the III-nitride photovoltaic device that increases the light collection efficiency of the III-nitride photovoltaic device. The III-nitride photovoltaic device includes one or more III-nitride device layers, and the III-nitride photovoltaic device functions by collecting light that is incident on the back-side of the III-nitride device layers. The III-nitride device layers are grown on a substrate, wherein the III-nitride device layers are exposed when the substrate is removed and the exposed III-nitride device layers are then intentionally roughened to enhance their light collection efficiency. The collection of the incident light via the back-side of the device simplifies the fabrication of the multiple junctions in the device. The III-nitride photovoltaic device may include grid-like contacts, transparent or semi-transparent contacts, or reflective contacts.
    Type: Application
    Filed: October 21, 2011
    Publication date: July 19, 2012
    Applicant: THE REGENTS OF THE UNIVERSITY OF CALIFORNIA
    Inventors: Robert M. Farrell, Carl J. Neufeld, Nikholas G. Toledo, Steven P. DenBaars, Umesh K. Mishra, James S. Speck, Shuji Nakamura
  • Patent number: 8211723
    Abstract: A method for fabricating AlxGa1-xN-cladding-free nonpolar III-nitride based laser diodes or light emitting diodes. Due to the absence of polarization fields in the nonpolar crystal planes, these nonpolar devices have thick quantum wells that function as an optical waveguide to effectively confine the optical mode to the active region and eliminate the need for Al-containing waveguide cladding layers.
    Type: Grant
    Filed: February 12, 2008
    Date of Patent: July 3, 2012
    Assignee: The Regents of the University of California
    Inventors: Daniel F. Feezell, Mathew C. Schmidt, Kwang-Choong Kim, Robert M. Farrell, Daniel A. Cohen, James S. Speck, Steven P. DenBaars, Shuji Nakamura
  • Publication number: 20120161287
    Abstract: A method for growing a semi-polar nitride semiconductor thin film via metalorganic chemical vapor deposition (MOCVD) on a substrate, wherein a nitride nucleation or buffer layer is grown on the substrate prior to the growth of the semi-polar nitride semiconductor thin film.
    Type: Application
    Filed: January 17, 2012
    Publication date: June 28, 2012
    Applicants: JAPAN SCIENCE AND TECHNOLOGY AGENCY, THE REGENTS OF THE UNIVERSITY OF CALIFORNIA
    Inventors: Michael Iza, Troy J. Baker, Benjamin A. Haskell, Steven P. DenBaars, Shuji Nakamura