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).

  • High light extraction efficiency nitride based light emitting diode by surface roughening
    Patent number: 8835200
    Abstract: A III-nitride light emitting diode (LED) and method of fabricating the same, wherein at least one surface of a semipolar or nonpolar plane of a III-nitride layer of the LED is textured, thereby forming a textured surface in order to increase light extraction. The texturing may be performed by plasma assisted chemical etching, photolithography followed by etching, or nano-imprinting followed by etching.
    Type: Grant
    Filed: January 12, 2012
    Date of Patent: September 16, 2014
    Assignee: The Regents of the University of California
    Inventors: Hong Zhong, Anurag Tyagi, Kenneth J. Vampola, James S. Speck, Steven P. DenBaars, Shuji Nakamura
  • Transparent light emitting diodes
    Patent number: 8835959
    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: September 19, 2012
    Date of Patent: September 16, 2014
    Assignee: The Regents of the University of California
    Inventors: Shuji Nakamura, Steven P. DenBaars, Hirokuni Asamizu
  • Rare earth doped layer or substrate for light conversion
    Patent number: 8829546
    Abstract: A solid state light emitting device comprising an emitter structure having an active region of semiconductor material and a pair of oppositely doped layers of semiconductor material on opposite sides of the active region. The active region emits light at a predetermined wavelength in response to an electrical bias across the doped layers. An absorption layer of semiconductor material is included that is integral to said emitter structure and doped with at least one rare earth or transition element. The absorption layer absorbs at least some of the light emitted from the active region and re-emits at least one different wavelength of light. A substrate is included with the emitter structure and absorption layer disposed on the substrate.
    Type: Grant
    Filed: February 13, 2006
    Date of Patent: September 9, 2014
    Assignee: Cree, Inc.
    Inventors: Steven P. DenBaars, Eric J. Tarsa, Michael Mack, Bernd Keller, Brian Thibeault, Adam W. Saxler
  • Dislocation reduction in non-polar III-nitride thin films
    Patent number: 8809867
    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: Grant
    Filed: September 10, 2007
    Date of Patent: August 19, 2014
    Assignee: The Regents of the University of California
    Inventors: Michael D. Craven, Steven P. Denbaars, James S. Speck, Shuji Nakamura
  • Method of improving surface morphology of (Ga,Al,In,B)N thin films and devices grown on nonpolar or semipolar (Ga,Al,In,B)N substrates
    Patent number: 8795430
    Abstract: A method for improving the growth morphology of (Ga,Al,In,B)N thin films on nonpolar or semipolar (Ga,Al,In,B)N substrates, wherein a (Ga,Al,In,B)N thin film is grown directly on a nonpolar or semipolar (Ga,Al,In,B)N substrate or template and a portion of the carrier gas used during growth is comprised of an inert gas. Nonpolar or semipolar nitride LEDs and diode lasers may be grown on the smooth (Ga,Al,In,B)N thin films grown by the present invention.
    Type: Grant
    Filed: March 2, 2010
    Date of Patent: August 5, 2014
    Assignee: The Regents of the University of California
    Inventors: Robert M. Farrell, Michael Iza, James S. Speck, Steven P. DenBaars, Shuji Nakamura
  • Growth of non-polar M-plane III-nitride film using metalorganic chemical vapor deposition (MOCVD)
    Patent number: 8795440
    Abstract: A method of growing non-polar m-plane III-nitride film, such as GaN, AlN, AlGaN or InGaN, wherein the non-polar m-plane III-nitride film is grown on a suitable substrate, such as an m-SiC, m-GaN, LiGaO2 or LiAlO2 substrate, using metalorganic chemical vapor deposition (MOCVD). The method includes performing a solvent clean and acid dip of the substrate to remove oxide from the surface, annealing the substrate, growing a nucleation layer, such as aluminum nitride (AlN), on the annealed substrate, and growing the non-polar m-plane III-nitride film on the nucleation layer using MOCVD.
    Type: Grant
    Filed: December 7, 2011
    Date of Patent: August 5, 2014
    Assignees: The Regents of the University of California, Japan Science and Technology Agency
    Inventors: Bilge M. Imer, James S. Speck, Steven P. DenBaars, Shuji Nakamura
  • TECHNIQUE FOR THE GROWTH AND FABRICATION OF SEMIPOLAR (Ga,Al,In,B)N THIN FILMS, HETEROSTRUCTURES, AND DEVICES
    Publication number: 20140211820
    Abstract: A method for growth and fabrication of semipolar (Ga,Al,In,B)N thin films, heterostructures, and devices, comprising identifying desired material properties for a particular device application, selecting a semipolar growth orientation based on the desired material properties, selecting a suitable substrate for growth of the selected semipolar growth orientation, growing a planar semipolar (Ga,Al,In,B)N template or nucleation layer on the substrate, and growing the semipolar (Ga,Al,In,B)N thin films, heterostructures or devices on the planar semipolar (Ga,Al,In,B)N template or nucleation layer. The method results in a large area of the semipolar (Ga,Al,In,B)N thin films, heterostructures, and devices being parallel to the substrate surface.
    Type: Application
    Filed: March 28, 2014
    Publication date: July 31, 2014
    Applicants: Japan Science and Technology Agency, The Regents of the University of California
    Inventors: Robert M. Farrell, JR., Troy J. Baker, Arpan Chakraborty, Benjamin A. Haskell, P. Morgan Pattison, Rajat Sharma, Umesh K. Mishra, Steven P. DenBaars, James S. Speck, Shuji Nakamura
  • Planar nonpolar group-III nitride films grown on miscut substrates
    Patent number: 8791000
    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: Grant
    Filed: January 27, 2014
    Date of Patent: July 29, 2014
    Assignee: 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
  • (Al,Ga,In)N diode laser fabricated at reduced temperature
    Patent number: 8790943
    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: August 23, 2012
    Date of Patent: July 29, 2014
    Assignee: The Regents of the University of California
    Inventors: Daniel A. Cohen, Steven P. DenBaars, Shuji Nakamura
  • METHOD FOR CONDUCTIVITY CONTROL OF (Al,In,Ga,B)N
    Publication number: 20140191244
    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: March 12, 2014
    Publication date: July 10, 2014
    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
  • LED with surface roughening
    Patent number: 8772792
    Abstract: An LED having a p-type layer of material with an associated p-contact, an n-type layer of material with an associated n-contact and an active region between the p-type layer and the n-type layer, includes a roughened emitting-side surface to further enhance light extraction.
    Type: Grant
    Filed: August 23, 2013
    Date of Patent: July 8, 2014
    Assignee: Cree, Inc.
    Inventors: Steven P. DenBaars, Shuji Nakamura, Max Batres
  • Suppression of inclined defect formation and increase in critical thickness by silicon doping on non-c-plane (Al,Ga,In)N
    Patent number: 8772758
    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: Grant
    Filed: May 14, 2012
    Date of Patent: July 8, 2014
    Assignee: The Regents of the University of California
    Inventors: Matthew T. Hardy, Po Shan Hsu, Steven P. DenBaars, James S. Speck, Shuji Nakamura
  • MISCUT SEMIPOLAR OPTOELECTRONIC DEVICE
    Publication number: 20140183579
    Abstract: A method for improved growth of a semipolar (Al,In,Ga,B)N semiconductor thin film using an intentionally miscut substrate. Specifically, the method comprises intentionally miscutting a substrate, loading a substrate into a reactor, heating the substrate under a flow of nitrogen and/or hydrogen and/or ammonia, depositing an InxGa1-xN nucleation layer on the heated substrate, depositing a semipolar nitride semiconductor thin film on the InxGa1-xN nucleation layer, and cooling the substrate under a nitrogen overpressure.
    Type: Application
    Filed: January 2, 2013
    Publication date: July 3, 2014
    Applicants: Japan Science and Technology Agency, The Regents of the University of California
    Inventors: John F. Kaeding, Dong-Seon Lee, Michael Iza, Troy J. Baker, Hitoshi Sato, Benjamin A. Haskell, James S. Speck, Steven P. DenBaars, Shuji Nakamura
  • Aluminum gallium nitride barriers and separate confinement heterostructure (SCH) layers for semipolar plane III-nitride semiconductor-based light emitting diodes and laser diodes
    Patent number: 8761218
    Abstract: A semipolar plane III-nitride semiconductor-based laser diode or light emitting diode, comprising a semipolar Indium containing multiple quantum wells for emitting light, having Aluminum containing quantum well barriers, wherein the Indium containing multiple quantum well and Aluminum containing barriers are grown in a semipolar orientation on a semipolar plane.
    Type: Grant
    Filed: April 5, 2011
    Date of Patent: June 24, 2014
    Assignee: The Regents of the University of California
    Inventors: You-Da Lin, Hiroaki Ohta, Shuji Nakamura, Steven P. DenBaars, James S. Speck
  • PEC ETCHING OF (20-2-1) SEMIPOLAR GALLIUM NITRIDE FOR EXTERNAL EFFICIENCY ENHANCEMENT IN LIGHT EMITTING DIODE APPLICATIONS
    Publication number: 20140167059
    Abstract: A method of performing a photoelectrochemical (PEC) etch on an exposed surface of a semipolar {20-2-1} III-nitride semiconductor, for improving light extraction from and for enhancing external efficiency of one or more active layers formed on or above the semipolar {20-2-1} III-nitride semiconductor.
    Type: Application
    Filed: August 30, 2013
    Publication date: June 19, 2014
    Inventors: Chung-Ta Hsu, Chia-Yen Huang, Yuji Zhao, Shih-Chieh Haung, Daniel F. Feezell, Steven P. DenBaars, Shuji Nakamura, James S. Speck
  • LOW DROOP LIGHT EMITTING DIODE STRUCTURE ON GALLIUM NITRIDE SEMIPOLAR SUBSTRATES
    Publication number: 20140151634
    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: February 6, 2014
    Publication date: June 5, 2014
    Applicant: THE REGENTS OF THE UNIVERSITY OF CALIFORNIA
    Inventors: Shuji Nakamura, Steven P. DenBaars, Shinichi Tanaka, Daniel F. Feezell, Yuji Zhao, Chih-Chien Pan
  • PLANAR NONPOLAR GROUP-III NITRIDE FILMS GROWN ON MISCUT SUBSTRATES
    Publication number: 20140138679
    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: January 27, 2014
    Publication date: May 22, 2014
    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
  • Method for increasing the area of non-polar and semi-polar nitride substrates
    Patent number: 8729671
    Abstract: A method for fabricating a high quality freestanding nonpolar and semipolar nitride substrate with increased surface area, comprising stacking multiple films by growing the films one on top of each other with different and non-orthogonal growth directions.
    Type: Grant
    Filed: December 15, 2011
    Date of Patent: May 20, 2014
    Assignee: The Regents of the University of California
    Inventors: Asako Hirai, James S. Speck, Steven P. DenBaars, Shuji Nakamura
  • (IN,GA,AL)N OPTOELECTRONIC DEVICES GROWN ON RELAXED (IN,GA,AL)N-ON-GAN BASE LAYERS
    Publication number: 20140131730
    Abstract: A method of fabricating a heterostructure device, including (a) obtaining a first layer or substrate; (b) growing a second layer on the first layer or substrate; and (c) forming the second layer that is at least partially relaxed wherein (1) the first layer and the second layer have the same lattice structure but different lattice constants, (2) the first layer and the second layer form a heterojunction, and (3) the heterojunction forms an active area of a device or serves as a pseudo-substrate for the device.
    Type: Application
    Filed: November 6, 2013
    Publication date: May 15, 2014
    Inventors: Stacia Keller, Carl J. Neufeld, Umesh K. Mishra, Steven P. DenBaars
  • WHITE LIGHT SOURCE EMPLOYING A III-NITRIDE BASED LASER DIODE PUMPING A PHOSPHOR
    Publication number: 20140126200
    Abstract: A white light source employing a III-nitride based laser diode pumping one or more phosphors. The III-nitride laser diode emits light in a first wavelength range that is down-converted to light in a second wavelength range by the phosphors, wherein the light in the first wavelength range is combined with the light in the second wavelength range to create highly directional white light. The light in the first wavelength range comprises ultraviolet, violet, blue and/or green light, while the light in the second wavelength range comprises green, yellow and/or red light.
    Type: Application
    Filed: October 29, 2013
    Publication date: May 8, 2014
    Inventors: Kathryn M. Kelchner, James S. Speck, Nathan A. Pfaff, Steven P. DenBaars