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).

  • Publication number: 20090039356
    Abstract: A nonpolar III-nitride film grown on a miscut angle of a substrate. The miscut angle towards the <000-1> direction is 0.75° or greater miscut and less than 27° miscut towards the <000-1> direction. Surface undulations are suppressed and may comprise faceted pyramids. A device fabricated using the film is also disclosed. A nonpolar III-nitride film having a smooth surface morphology fabricated using a method comprising selecting a miscut angle of a substrate upon which the nonpolar III-nitride films are grown in order to suppress surface undulations of the nonpolar III-nitride films. A nonpolar III-nitride-based device grown on a film having a smooth surface morphology grown on a miscut angle of a substrate which the nonpolar III-nitride films are grown. The miscut angle may also be selected to achieve long wavelength light emission from the nonpolar film.
    Type: Application
    Filed: August 8, 2008
    Publication date: February 12, 2009
    Applicant: THE REGENTS OF THE UNIVERSITY OF CALIFORNIA
    Inventors: Kenji Iso, Hisashi Yamada, Makoto Saito, Asako Hirai, Steven P. DenBaars, James S. Speck, Shuji Nakamura
  • Publication number: 20090001399
    Abstract: A method for increasing the luminous efficacy of a white light emitting diode (WLED), comprising introducing optically functional interfaces between an LED die and a phosphor, and between the phosphor and an outer medium, wherein at least one of the interfaces between the phosphor and the LED die provides a reflectance for light emitted by the phosphor away from the outer medium and a transmittance for light emitted by the LED die. Thus, a WLED may comprise a first material which surrounds an LED die, a phosphor layer, and at least one additional layer or material which is transparent for direct LED emission and reflective for the phosphor emission, placed between the phosphor layer and the first material which surrounds the LED die.
    Type: Application
    Filed: June 27, 2008
    Publication date: January 1, 2009
    Applicant: THE REGENTS OF THE UNIVERSITY OF CALIFORNIA
    Inventors: Frederic S. Diana, Steven P. DenBaars, Shuji Nakamura
  • Publication number: 20090001519
    Abstract: Growth methods for planar, non-polar, Group-III nitride films are described. The resulting films are suitable for subsequent device regrowth by a variety of growth techniques.
    Type: Application
    Filed: September 9, 2008
    Publication date: January 1, 2009
    Applicants: THE REGENTS OF THE UNIVERSITY OF CALIFORNIA, THE JAPAN SCIENCE AND TECHNOLOGY CENTER
    Inventors: Benjamin A. Haskell, Paul T. Fini, Shigemasa Matsuda, Michael D. Craven, Steven P. DenBaars, James S. Speck, Shuji Nakamura
  • Publication number: 20080308907
    Abstract: A nonpolar III-nitride film grown on a miscut angle of a substrate, in order to suppress the surface undulations, is provided. The surface morphology of the film is improved with a miscut angle towards an a-axis direction comprising a 0.15° or greater miscut angle towards the a-axis direction and a less than 30° miscut angle towards the a-axis direction.
    Type: Application
    Filed: June 16, 2008
    Publication date: December 18, 2008
    Applicant: THE REGENTS OF THE UNIVERSITY OF CALIFORNIA
    Inventors: Asako Hirai, Zhongyuan Jia, Makoto Saito, Hisashi Yamada, Kenji Iso, Steven P. DenBaars, Shuji Nakamura, James S. Speck
  • Publication number: 20080283854
    Abstract: A light emitting diode device layer structure including a p-type contact layer that contains at least some indium (In), wherein the p-type contact layer is a not-intentionally doped strained nitride contact layer.
    Type: Application
    Filed: May 1, 2008
    Publication date: November 20, 2008
    Applicant: THE REGENTS OF THE UNIVERSITY OF CALIFORNIA
    Inventors: Michael Iza, Hirokuni Asamizu, Christian G. Van de Walle, Steven P. DenBaars, Shuji Nakamura
  • Publication number: 20080277682
    Abstract: A light emitting diode, comprising a substrate, a buffer layer on the substrate, an active layer on the buffer layer and between an n-type layer and a p-type layer, a tunnel junction adjacent the p-type layer, and n-type contacts to the tunnel junction and the n-type layer, wherein the buffer layer, n-type layer, p-type layer, active region and tunnel junction comprise III-nitride material grown in a nitrogen-face (N-face) orientation. The substrate surface upon which the III-nitride material is deposited is patterned to provide embedded backside roughening. A top surface of the tunnel junction, which also the top surface of the III-nitride material, is roughened.
    Type: Application
    Filed: March 31, 2008
    Publication date: November 13, 2008
    Applicant: THE REGENTS OF THE UNIVERSITY OF CALIFORNIA
    Inventors: Umesh K. Mishra, Michael Grundmann, Steven P. DenBaars, Shuji Nakamura
  • Publication number: 20080251802
    Abstract: A method for growing an improved quality nitride thin film on a patterned substrate is disclosed, wherein the nitride film is grown at atmospheric pressure. A nitride template is disclosed, comprising a patterned substrate and a one or more nitride layer direct growth off of the patterned substrate, comprising no lateral epitaxial overgrowth regions and a substantially coalesced surface smooth enough for subsequent deposition of light emitting device quality nitride layers onto the surface. A light emitting diode comprising the nitride film is also disclosed.
    Type: Application
    Filed: April 14, 2008
    Publication date: October 16, 2008
    Applicant: THE REGENTS OF THE UNIVERSITY OF CALIFORNIA
    Inventors: Michael Iza, Steven P. DenBaars, Shuji Nakamura
  • Patent number: 7427555
    Abstract: Highly planar non-polar GaN films are grown by hydride vapor phase epitaxy (HVPE). The resulting films are suitable for subsequent device regrowth by a variety of growth techniques.
    Type: Grant
    Filed: July 15, 2003
    Date of Patent: September 23, 2008
    Assignees: The Regents of the University of California, The Japan Science and Technology Agency
    Inventors: Benjamin A. Haskell, Paul T. Fini, Shigemasa Matsuda, Michael D. Craven, Steven P. DenBaars, James S. Speck, Shuji Nakamura
  • Publication number: 20080198881
    Abstract: Optical gain of a nonpolar or semipolar Group-III nitride diode laser is controlled by orienting an axis of light propagation in relation to an optical polarization direction or crystallographic orientation of the diode laser. The axis of light propagation is substantially perpendicular to the mirror facets of the diode laser, and the optical polarization direction is determined by the crystallographic orientation of the diode laser. To maximize optical gain, the axis of light propagation is oriented substantially perpendicular to the optical polarization direction or crystallographic orientation.
    Type: Application
    Filed: February 12, 2008
    Publication date: August 21, 2008
    Applicant: THE REGENTS OF THE UNIVERSITY OF CALIFORNIA
    Inventors: Robert M. Farrell, Mathew C. Schmidt, Kwang Choong Kim, Hisashi Masui, Daniel F. Feezell, James S. Speck, Steven P. DenBaars, Shuji Nakamura
  • Publication number: 20080191192
    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: February 12, 2008
    Publication date: August 14, 2008
    Applicant: THE REGENTS OF THE UNIVERSITY OF CALIFORNIA
    Inventors: Daniel F. Feezell, Matthew C. Schmidt, Kwang Choong Kim, Robert M. Farrell, Daniel A. Cohen, James S. Speck, Steven P. DenBaars, Shuji Nakamura
  • Publication number: 20080191223
    Abstract: A III-nitride edge-emitting laser diode is formed on a surface of a III-nitride substrate having a semipolar orientation, wherein the III-nitride substrate is cleaved by creating a cleavage line along a direction substantially perpendicular to a nonpolar orientation of the III-nitride substrate, and then applying force along the cleavage line to create one or more cleaved facets of the III-nitride substrate, wherein the cleaved facets have an m-plane or a-plane orientation.
    Type: Application
    Filed: February 12, 2008
    Publication date: August 14, 2008
    Applicant: THE REGENTS OF THE UNIVERSITY OF CALIFORNIA
    Inventors: Shuji Nakamura, James S. Speck, Steven P. DenBaars, Anurag Tyagi
  • Publication number: 20080185690
    Abstract: A method of reducing threading dislocation densities in non-polar such as a-{11-20} plane and m-{1-100} plane or semi-polar such as {10-1n} plane III-Nitrides by employing lateral epitaxial overgrowth from sidewalls of etched template material through a patterned mask. The method includes depositing a patterned mask on a template material such as a non-polar or semi polar GaN template, etching the template material down to various depths through openings in the mask, and growing non-polar or semi-polar III-Nitride by coalescing laterally from the tops of the sidewalls before the vertically growing material from the trench bottoms reaches the tops of the sidewalls. The coalesced features grow through the openings of the mask, and grow laterally over the dielectric mask until a fully coalesced continuous film is achieved.
    Type: Application
    Filed: March 3, 2008
    Publication date: August 7, 2008
    Applicants: The Regents of the University of California, Japan Science and Technology Agency
    Inventors: Bilge M. Imer, James S. Speck, Steven P. DenBaars
  • Publication number: 20080179607
    Abstract: An (Al, Ga, In)N light emitting device, such as a light emitting diode (LED), in which high light generation efficiency is realized by fabricating the device on non-polar or semi-polar III-Nitride crystal geometries. Because non-polar and semi-polar emitting devices have significantly lower piezoelectric effects than c-plane emitting devices, higher efficiency emitting devices at higher current densities can be realized.
    Type: Application
    Filed: December 11, 2007
    Publication date: July 31, 2008
    Applicants: The Regents of the University of California, Japan Science and Technology Agency
    Inventors: Steven P. DenBaars, Mathew C. Schmidt, Kwang Choong Kim, James S. Speck, Shuji Nakamura
  • Publication number: 20080164489
    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: December 11, 2007
    Publication date: July 10, 2008
    Applicants: The Regents of the University of California, Japan Science and Technology Agency
    Inventors: Mathew C. Schmidt, Kwang Choong Kim, Hitoshi Sato, Steven P. DenBaars, James S. Speck, Shuji Nakamura
  • Publication number: 20080163814
    Abstract: A method of reducing threading dislocation densities in non-polar such as a- {11-20} plane and m-{1-100} plane or semi-polar such as {10-1n} plane III-Nitrides by employing lateral epitaxial overgrowth from sidewalls of etched template material through a patterned mask. The method includes depositing a patterned mask on a template material such as a non-polar or semi polar GaN template, etching the template material down to various depths through openings in the mask, and growing non-polar or semi-polar III-Nitride by coalescing laterally from the tops of the sidewalls before the vertically growing material from the trench bottoms reaches the tops of the sidewalls. The coalesced features grow through the openings of the mask, and grow laterally over the dielectric mask until a fully coalesced continuous film is achieved.
    Type: Application
    Filed: December 11, 2007
    Publication date: July 10, 2008
    Applicant: THE REGENTS OF THE UNIVERSITY OF CALIFORNIA
    Inventors: Kwang Choong Kim, Mathew C. Schmidt, Feng Wu, Asako Hirai, Melvin B. McLaurin, Steven P. DenBaars, Shuji Nakamura, James S. Speck
  • Publication number: 20080149959
    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: Application
    Filed: December 11, 2007
    Publication date: June 26, 2008
    Applicant: THE REGENTS OF THE UNIVERSITY OF CALIFORNIA
    Inventors: Shuji Nakamura, Steven P. DenBaars, Hirokuni Asamizu
  • Publication number: 20080149949
    Abstract: A lead frame for a transparent and mirrorless light emitting diode (LED). The LED is comprised of 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. A lead frame supports the III-nitride layers, wherein the III-nitride layers reside on a transparent plate in the lead frame, and the light emitted from the III-nitride layers is transmitted through the transparent plate. A metal mask may be formed on the transparent plate for electrically connecting the III-nitride layers to a lead frame.
    Type: Application
    Filed: December 11, 2007
    Publication date: June 26, 2008
    Applicant: THE REGENTS OF THE UNIVERSITY OF CALIFORNIA
    Inventors: Shuji Nakamura, Steven P. DenBaars
  • Publication number: 20080135864
    Abstract: Light Emitting Diodes (LEDs) where the emission region, usually a (Al,In,Ga)N layer, is structured for efficient light extraction, are disclosed. The structuring is designed for light extraction from thin films, such as a photonic crystal acting as a diffraction grating. In addition, the structuring controls the in-plane emission and allows new modes into which light will be emitted. Various electrode designs are proposed, including ZnO structures which are known to lead to both excellent electrical properties, such as good carrier injection, and high transparency. Alternatively, the (Al,In,Ga)N layer can be replaced by structures with other materials compositions, in order to achieve efficient light extraction.
    Type: Application
    Filed: November 15, 2007
    Publication date: June 12, 2008
    Applicant: THE REGENTS OF THE UNIVERSITY OF CALIFORNIA
    Inventors: Aurelien J. F. David, Claude C. A. Weisbuch, Steven P. DenBaars, Stacia Keller
  • Publication number: 20080135853
    Abstract: Lateral epitaxial overgrowth of non-polar III-nitride seed layers reduces threading dislocations in the non-polar III-nitride thin films. First, a thin patterned dielectric mask is applied to the seed layer. Second, a selective epitaxial regrowth is performed to achieve a lateral overgrowth based on the patterned mask. Upon regrowth, the non-polar III-nitride films initially grow vertically through openings in the dielectric mask before laterally overgrowing the mask in directions perpendicular to the vertical growth direction. Threading dislocations are reduced in the overgrown regions by (1) the mask blocking the propagation of dislocations vertically into the growing film and (2) the bending of dislocations through the transition from vertical to lateral growth.
    Type: Application
    Filed: September 10, 2007
    Publication date: June 12, 2008
    Applicant: The Regents of the University of California
    Inventors: Michael D. Craven, Steven P. DenBaars, James S. Speck, Shuji Nakamura
  • Publication number: 20080128737
    Abstract: A structure using integrated optical elements is comprised of a substrate, a buffer layer grown on the substrate, one or more patterned layers formed on the buffer layer and one or more active layers formed on or between the patterned layers, for instance by Lateral Epitaxial Overgrowth (LEO), and including one or more light emitting species. The patterned layer comprises a mask (made of insulating, semiconducting or metallic material) and material filling holes in the mask. The patterned layer, due to a large index difference with the active layer and/or variations of a refractive index between the mask and materials filling holes in the mask, acts as an optical confinement layer, a mirror, a diffraction grating, a wavelength selective element, a beam shaping element or a beam directing element.
    Type: Application
    Filed: February 13, 2008
    Publication date: June 5, 2008
    Applicant: THE REGENTS OF THE UNIVERSITY OF CALIFORNIA
    Inventors: Claude C.A. Weisbuch, Aurelien J.F. David, James S. Speck, Steven P. Denbaars