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).

  • OHMIC CATHODE ELECTRODE ON THE BACKSIDE OF NONPOLAR M-PLANE (1-100) AND SEMIPOLAR (20-21) BULK GALLIUM NITRIDE SUBSTRATES
    Publication number: 20120153297
    Abstract: Ohmic cathode electrodes are formed on the backside of nonpolar m-plane (1-100) and semipolar (20-21) bulk gallium nitride (GaN) substrates. The GaN substrates are thinned using a mechanical polishing process. For m-plane GaN, after the thinning process, dry etching is performed, followed by metal deposition, resulting in ohmic I-V characteristics for the contact. For (20-21) GaN, after the thinning process, dry etching is performed, followed by metal deposition, followed by annealing, resulting in ohmic I-V characteristics for the contact as well.
    Type: Application
    Filed: August 1, 2011
    Publication date: June 21, 2012
    Applicant: THE REGENTS OF THE UNIVERSITY OF CALIFORNIA
    Inventors: Chia-Lin Hsiung, You-Da Lin, Hiroaki Ohta, Steven P. DenBaars, Shuji Nakamura
  • Method for growth of semipolar (Al,In,Ga,B)N optoelectronic devices
    Patent number: 8203159
    Abstract: A method of fabricating an optoelectronic device, comprising growing an active layer of the device on an oblique surface of a suitable material, wherein the oblique surface comprises a facetted surface. The present invention also discloses a method of fabricating the facetted surfaces. One fabrication process comprises growing an epitaxial layer on a suitable material, etching the epitaxial layer through a mask to form the facets having a specific crystal orientation, and depositing one or more active layers on the facets. Another method comprises growing a layer of material using a lateral overgrowth technique to produce a facetted surface, and depositing one or more active layers on the facetted surfaces. The facetted surfaces are typically semipolar planes.
    Type: Grant
    Filed: September 24, 2010
    Date of Patent: June 19, 2012
    Assignee: The Regents of the University of California
    Inventors: Hong Zhong, John F. Kaeding, Rajat Sharma, James S. Speck, Steven P. DenBaars, Shuji Nakamura
  • METHOD FOR REDUCTION OF EFFICIENCY DROOP USING AN (Al,In,Ga)N/Al(x)In(1-x)N SUPERLATTICE ELECTRON BLOCKING LAYER IN NITRIDE BASED LIGHT EMITTING DIODES
    Publication number: 20120138891
    Abstract: A method for reduction of efficiency droop using an (Al, In, Ga)N/AlxIn1-xN superlattice electron blocking layer (SL-EBL) in nitride based light emitting diodes.
    Type: Application
    Filed: October 27, 2011
    Publication date: June 7, 2012
    Applicant: THE REGENTS OF THE UNIVERSITY OF CALIFORNIA
    Inventors: Roy B. Chung, Changseok Han, Steven P. DenBaars, James S. Speck, Shuji Nakamura
  • Method for conductivity control of (Al,In,Ga,B)N
    Patent number: 8193079
    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: Grant
    Filed: February 9, 2007
    Date of Patent: June 5, 2012
    Assignee: The Regents of the University of California
    Inventors: John F. Kaeding, Hitoshi Sato, Michael Iza, Hirokuni Asamizu, Hong Zhong, Steven P. DenBaars, Shuji Nakamura
  • Non-polar (Al,B,In,Ga)N quantum well and heterostructure materials and devices
    Patent number: 8188458
    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 (1 102) 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: Grant
    Filed: May 3, 2011
    Date of Patent: May 29, 2012
    Assignee: The Regents of the University of California
    Inventors: Michael D. Craven, Stacia Keller, Steven P. DenBaars, Tal Margalith, James S. Speck, Shuji Nakamura, Umesh K. Mishra
  • HIGH POWER, HIGH EFFICIENCY AND LOW EFFICIENCY DROOP III-NITRIDE LIGHT-EMITTING DIODES ON SEMIPOLAR SUBSTRATES
    Publication number: 20120126283
    Abstract: A III-nitride light emitting diode grown on a semipolar {20-2-1} plane of a substrate and characterized by high power, high efficiency and low efficiency droop.
    Type: Application
    Filed: October 27, 2011
    Publication date: May 24, 2012
    Applicant: THE REGENTS OF THE UNIVERSITY OF CALIFORNIA
    Inventors: Yuji Zhao, Junichi Sonoda, Chih-Chien Pan, Shinichi Tanaka, Steven P. DenBaars, Shuji Nakamura
  • LIGHT EMITTING DIODE FOR DROOP IMPROVEMENT
    Publication number: 20120126198
    Abstract: A light emitting diode (LED) device structure with a reduced Droop effect, and a method for fabricating the LED device structure. The LED is a III-nitride-based LED having an active layer or emitting layer comprised of a multi-quantum-well (MQW) structure, wherein there are eight or more quantum wells (QWs) in the MQW structure, and more preferably, at least nine QWs in the MQW structure. Moreover, the QWs in the MQW structure are grown at temperatures different from barrier layers in the MQW structure, wherein the barrier layers in the MQW structure are grown a temperatures at least 40° C. higher than the QWs in the MQW structure.
    Type: Application
    Filed: October 27, 2011
    Publication date: May 24, 2012
    Applicant: THE REGENTS OF THE UNIVERSITY OF CALIFORNIA
    Inventors: Shuji Nakamura, Steven P. DenBaars, Shinichi Tanaka, Junichi Sonoda, Hung Tse Chen, Chih-Chien Pan
  • (Al,In,Ga,B)N device structures on a patterned substrate
    Patent number: 8183557
    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: Grant
    Filed: September 19, 2008
    Date of Patent: May 22, 2012
    Assignee: The Regents of the University of California
    Inventors: Michael Iza, Hitoshi Sato, Eu Jin Hwang, Steven P. DenBaars, Shuji Nakamura
  • TECHNIQUE FOR THE GROWTH OF PLANAR SEMI-POLAR GALLIUM NITRIDE
    Publication number: 20120119222
    Abstract: A method for growing planar, semi-polar nitride film on a miscut spinel substrate, in which a large area of the planar, semi-polar nitride film is parallel to the substrate's surface. The planar films and substrates are: (1) {1011} gallium nitride (GaN) grown on a {100} spinel substrate miscut in specific directions, (2) {1013} gallium nitride (GaN) grown on a {110} spinel substrate, (3) {1122} gallium nitride (GaN) grown on a {1100} sapphire substrate, and (4) {1013} gallium nitride (GaN) grown on a {1100} sapphire substrate.
    Type: Application
    Filed: January 24, 2012
    Publication date: May 17, 2012
    Applicant: THE REGENTS OF THE UNIVERSITY OF CALIFORNIA
    Inventors: Troy J. Baker, Benjamin A. Haskell, Paul T. Fini, Steven P. DenBaars, James S. Speck, Shuji Nakamua
  • Metalorganic chemical vapor deposition (MOCVD) growth of high performance non-polar III-nitride optical devices
    Patent number: 8178373
    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: Grant
    Filed: October 28, 2010
    Date of Patent: May 15, 2012
    Assignees: The Regents of the University of California, Japan Science and Technology Agency
    Inventors: Mathew C. Schmidt, Kwang Choong Kim, Hitsohi Sato, Steven P. DenBaars, James S. Speck, Shuji Nakamura
  • MAGNESIUM DOPING IN BARRIERS IN MULTIPLE QUANTUM WELL STRUCTURES OF III-NITRIDE-BASED LIGHT EMITTING DEVICES
    Publication number: 20120107991
    Abstract: A III-nitride-based light emitting device having a multiple quantum well (MQW) structure and a method for fabricating the device, wherein at least one barrier in the MQW structure is doped with magnesium (Mg). The Mg doping of the barrier is accomplished by introducing a bis(cyclopentadienyl)magnesium (Cp2Mg) flow during growth of the barrier using metalorganic chemical vapor deposition (MOCVD). The barriers of the MQW structure may be undoped, fully Mg-doped or partially Mg-doped. When the barrier is partially Mg-doped, only portions of the barrier are Mg-doped to prevent Mg diffusion into quantum wells of the MQW structure. The Mg-doped barriers preferably are high Al composition AlGaN barriers in nonpolar or semipolar devices.
    Type: Application
    Filed: October 21, 2011
    Publication date: May 3, 2012
    Applicant: THE REGENTS OF THE UNIVERSITY OF CALIFORNIA
    Inventors: Chia-Yen Huang, Shuji Nakamura, Steven P. DenBaars, James S. Speck
  • STRAIN COMPENSATED SHORT-PERIOD SUPERLATTICES ON SEMIPOLAR OR NONPOLAR GAN FOR DEFECT REDUCTION AND STRESS ENGINEERING
    Publication number: 20120104360
    Abstract: An (AlInGaN) based semiconductor device, comprising a first layer that is a semipolar or nonpolar nitride (AlInGaN) layer having a lattice constant that is partially or fully relaxed, deposited on a substrate or a template, wherein there are one or more dislocations at a heterointerface between the first layer and the substrate or the template; one or more strain compensated layers on the first layer, for defect reduction and stress engineering in the device, that is lattice matched to a larger lattice constant of the first layer; and one or more nonpolar or semipolar (AlInGaN) device layers on the strain compensated layers.
    Type: Application
    Filed: October 28, 2011
    Publication date: May 3, 2012
    Applicant: THE REGENTS OF THE UNIVERSITY OF CALIFORNIA
    Inventors: Matthew T. Hardy, Steven P. DenBaars, James S. Speck, Shuji Nakamura
  • GROUP-III NITRIDE SOLAR CELLS GROWN ON HIGH QUALITY GROUP-III NITRIDE CRYSTALS MOUNTED ON FOREIGN MATERIAL
    Publication number: 20120103419
    Abstract: A group-III nitride solar cell is grown on a thin piece of a group-III nitride crystal that has been mounted on a carrier comprised of a foreign material. The thin piece is a thin layer with a thickness that ranges from approximately 5 microns to approximately 300 microns.
    Type: Application
    Filed: October 25, 2011
    Publication date: May 3, 2012
    Applicant: THE REGENTS OF THE UNIVERSITY OF CALIFORNIA
    Inventors: Siddha Pimputkar, Shuji Nakamura, Steven P. DenBaars
  • TEXTURED III-V SEMICONDUCTOR
    Publication number: 20120104411
    Abstract: A method for fabricating a III-nitride semiconductor film, comprising depositing or growing a III-nitride semiconductor film in a semiconductor light absorbing or light emitting device structure; and growing a textured or structured surface of the III-nitride nitride semiconductor film in situ with the growing or the deposition of the III-nitride semiconductor film, by controlling the growing of the III-nitride semiconductor film to obtain a texture of the textured surface, or one or more structures of the structured surface, that increase output power of light from the light emitting device, or increase absorption of light in the light absorbing device.
    Type: Application
    Filed: October 27, 2011
    Publication date: May 3, 2012
    Applicant: THE REGENTS OF THE UNIVERSITY OF CALIFORNIA
    Inventors: Michael Iza, Carl J. Neufeld, Samantha C. Cruz, Robert M. Farrell, James S. Speck, Shuji Nakamura, Steven P. DenBaars, Umesh K. Mishra
  • HIGH LIGHT EXTRACTION EFFICIENCY NITRIDE BASED LIGHT EMITTING DIODE BY SURFACE ROUGHENING
    Publication number: 20120104412
    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: Application
    Filed: January 12, 2012
    Publication date: May 3, 2012
    Applicant: THE REGENTS OF THE UNIVERSITY OF CALIFORNIA
    Inventors: Hong Zhong, Anurag Tyagi, Kenneth J. Vampola, James S. Speck, Steven P. DenBaars, Shuji Nakamura
  • VICINAL SEMIPOLAR III-NITRIDE SUBSTRATES TO COMPENSATE TILT OF RELAXED HETERO-EPITAXIAL LAYERS
    Publication number: 20120100650
    Abstract: A method for fabricating a semi-polar III-nitride substrate for semi-polar III-nitride device layers, comprising providing a vicinal surface of the III-nitride substrate, so that growth of relaxed heteroepitaxial III-nitride device layers on the vicinal surface compensates for epilayer tilt of the III-nitride device layers caused by one or more misfit dislocations at one or more heterointerfaces between the device layers.
    Type: Application
    Filed: October 26, 2011
    Publication date: April 26, 2012
    Applicant: THE REGENTS OF THE UNIVERSITY OF CALIFORNIA
    Inventors: James S. Speck, Anurag Tyagi, Alexey E. Romanov, Shuji Nakamura, Steven P. DenBaars
  • DEFECT REDUCTION OF NON-POLAR AND SEMI-POLAR III-NITRIDES WITH SIDEWALL LATERAL EPITAXIAL OVERGROWTH (SLEO)
    Publication number: 20120098102
    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: April 25, 2011
    Publication date: April 26, 2012
    Applicants: THE REGENTS OF THE UNIVERSITY OF CALIFORNIA
    Inventors: Bilge M. Imer, James S. Speck, Steven P. DenBaars
  • LIMITING STRAIN RELAXATION IN III-NITRIDE HETERO-STRUCTURES BY SUBSTRATE AND EPITAXIAL LAYER PATTERNING
    Publication number: 20120097919
    Abstract: A method of fabricating a substrate for a semipolar III-nitride device, comprising patterning and forming one or more mesas on a surface of a semipolar III-nitride substrate or epilayer, thereby forming a patterned surface of the semipolar III-nitride substrate or epilayer including each of the mesas with a dimension/along a direction of a threading dislocation glide, wherein the threading dislocation glide results from a III-nitride layer deposited heteroepitaxially and coherently on a non-patterned surface of the substrate or epilayer.
    Type: Application
    Filed: October 26, 2011
    Publication date: April 26, 2012
    Applicant: THE REGENTS OF THE UNIVERSITY OF CALIFORNIA
    Inventors: James S. Speck, Anurag Tyagi, Steven P. DenBaars, Shuji Nakamura
  • Yellow emitting phosphors based on Ce-doped aluminate and via solid solution for solid-state lighting applications
    Patent number: 8163203
    Abstract: A Ce3+ based aluminate phosphor or Ce3+ based phosphor in a solid solution can be used for white light generation when combined with a blue or ultraviolet light emitting diode.
    Type: Grant
    Filed: February 27, 2009
    Date of Patent: April 24, 2012
    Assignee: The Regents of the University of California
    Inventors: Won-bin Im, Ram Seshadri, Steven P. DenBaars
  • IN-SITU DEFECT REDUCTION TECHNIQUES FOR NONPOLAR AND SEMIPOLAR (Al, Ga, In)N
    Publication number: 20120091467
    Abstract: A method for growing reduced defect density planar gallium nitride (GaN) films is disclosed. The method includes the steps of (a) growing at least one silicon nitride (SiNx) nanomask layer over a GaN template, and (b) growing a thickness of a GaN film on top of the SiNx nanomask layer.
    Type: Application
    Filed: December 20, 2011
    Publication date: April 19, 2012
    Applicant: THE REGENTS OF THE UNIVERSITY OF CALIFORNIA
    Inventors: Arpan Chakraborty, Kwang-Choong Kim, James S. Speck, Steven P. DenBaars, Umesh K. Mishra