Patents by Inventor Steven DenBaars

Steven 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: 7769066
    Abstract: A laser diode and method for fabricating same, wherein the laser diode generally comprises an InGaN compliance layer on a GaN n-type contact layer and an AlGaN/GaN n-type strained super lattice (SLS) on the compliance layer. An n-type GaN separate confinement heterostructure (SCH) is on said n-type SLS and an InGaN multiple quantum well (MQW) active region is on the n-type SCH. A GaN p-type SCH on the MQW active region, an AlGaN/GaN p-type SLS is on the p-type SCH, and a p-type GaN contact layer is on the p-type SLS. The compliance layer has an In percentage that reduces strain between the n-type contact layer and the n-type SLS compared to a laser diode without the compliance layer. Accordingly, the n-type SLS can be grown with an increased Al percentage to increase the index of refraction. This along with other features allows for reduced threshold current and voltage operation.
    Type: Grant
    Filed: November 15, 2006
    Date of Patent: August 3, 2010
    Assignee: Cree, Inc.
    Inventors: Arpan Chakraborty, Monica Hansen, Steven Denbaars, Shuji Nakamura, George Brandes
  • Patent number: 7682944
    Abstract: A substrate comprising a trench lateral epitaxial overgrowth structure including a trench cavity, wherein the trench cavity includes a growth-blocking layer or patterned material supportive of a coalescent Pendeo layer thereon, on at least a portion of an inside surface of the trench. Such substrate is suitable for carrying out lateral epitaxial overgrowth to form a bridged lateral overgrowth formation overlying the trench cavity. The bridged lateral overgrowth formation provides a substrate surface on which epitaxial layers can be grown in the fabrication of microelectronic devices such as laser diodes, high electron mobility transistors, ultraviolet light emitting diodes, and other devices in which low dislocation density is critical. The epitaxial substrate structures of the invention can be formed without the necessity for deep trenches, such as are required in conventional Pendeo epitaxial overgrowth structures.
    Type: Grant
    Filed: December 14, 2007
    Date of Patent: March 23, 2010
    Assignee: Cree, Inc.
    Inventors: George R. Brandes, Arpan Chakraborty, Shuji Nakamura, Monica Hansen, Steven Denbaars
  • Publication number: 20090152565
    Abstract: A substrate comprising a trench lateral epitaxial overgrowth structure including a trench cavity, wherein the trench cavity includes a growth-blocking layer or patterned material supportive of a coalescent Pendeo layer thereon, on at least a portion of an inside surface of the trench. Such substrate is suitable for carrying out lateral epitaxial overgrowth to form a bridged lateral overgrowth formation overlying the trench cavity. The bridged lateral overgrowth formation provides a substrate surface on which epitaxial layers can be grown in the fabrication of microelectronic devices such as laser diodes, high electron mobility transistors, ultraviolet light emitting diodes, and other devices in which low dislocation density is critical. The epitaxial substrate structures of the invention can be formed without the necessity for deep trenches, such as are required in conventional Pendeo epitaxial overgrowth structures.
    Type: Application
    Filed: December 14, 2007
    Publication date: June 18, 2009
    Inventors: George R. Brandes, Arpan Chakraborty, Shuji Nakamura, Monica Hansen, Steven Denbaars
  • Publication number: 20080112453
    Abstract: A laser diode comprising a first separate confinement heterostructure and an active region on the first separate confinement heterostructure. A second separate confinement heterostructure is on the active region and one or more epitaxial layers is on the second separate confinement heterostructure. A ridge is formed in the epitaxial layers with a first mesa around the ridge. The first mesa is 0.1 to 0.2 microns above the second confinement heterostructure.
    Type: Application
    Filed: November 15, 2006
    Publication date: May 15, 2008
    Inventors: Steven Denbaars, Shuji Nakamura, Monica Hansen
  • Publication number: 20080112452
    Abstract: A laser diode and method for fabricating same, wherein the laser diode generally comprises an InGaN compliance layer on a GaN n-type contact layer and an AlGaN/GaN n-type strained super lattice (SLS) on the compliance layer. An n-type GaN separate confinement heterostructure (SCH) is on said n-type SLS and an InGaN multiple quantum well (MQW) active region is on the n-type SCH. A GaN p-type SCH on the MQW active region, an AlGaN/GaN p-type SLS is on the p-type SCH, and a p-type GaN contact layer is on the p-type SLS. The compliance layer has an In percentage that reduces strain between the n-type contact layer and the n-type SLS compared to a laser diode without the compliance layer. Accordingly, the n-type SLS can be grown with an increased Al percentage to increase the index of refraction. This along with other features allows for reduced threshold current and voltage operation.
    Type: Application
    Filed: November 15, 2006
    Publication date: May 15, 2008
    Inventors: Arpan Chakraborty, Monica Hansen, Steven Denbaars, Shuji Nakamura, George Brandes
  • Publication number: 20080087909
    Abstract: A single or multi-color light emitting diode (LED) with high extraction efficiency is comprised of a substrate, a buffer layer formed on the substrate, one or more patterned layers deposited on top of the buffer layer, and one or more active layers formed on or between the patterned layers, for example by Lateral Epitaxial Overgrowth (LEO), and including one or more light emitting species, such as quantum wells. The patterned layers include a patterned, perforated or pierced mask made of insulating, semiconducting or metallic material, and materials filling holes in the mask. The patterned layer acts as an optical confining layer due to a contrast of a refractive index with the active layer and/or as a buried diffraction grating due to variation of a refractive index between the mask and the material filling the holes in the mask.
    Type: Application
    Filed: October 24, 2007
    Publication date: April 17, 2008
    Applicant: THE REGENTS OF THE UNIVERSITY OF CALIFORNIA
    Inventors: Claude Weisbuch, Aurelien David, James Speck, Steven DenBaars
  • Publication number: 20080061311
    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 confinement structure that is formed within one of the p-type layer of material and the n-type layer of material. The confinement structure is generally aligned with the contact on the top and primary emission surface of the LED and substantially prevents the emission of light from the area of the active region that is coincident with the area of the confinement structure and the top-surface contact. The LED may include a roughened emitting-side surface to further enhance light extraction.
    Type: Application
    Filed: November 9, 2007
    Publication date: March 13, 2008
    Inventors: Steven Denbaars, Shuji Nakamura, Max Batres
  • Patent number: 7332365
    Abstract: A method according to the present invention for fabricating high light extraction photonic devices comprising growing an epitaxial semiconductor structure on a substrate and depositing a first mirror layer on the epitaxial semiconductor structure such that the epitaxial semiconductor structure is sandwiched between the first mirror layer and the substrate. Flip-chip mounting the epitaxial semiconductor structure, with its first mirror and substrate on a submount such that the epitaxial semiconductor device structure is sandwiched between the submount and substrate. The substrate is then removed from the epitaxial structure by introducing an etch environment to the substrate. A second mirror layer is deposited on the epitaxial semiconductor structure such that the epitaxial semiconductor structure is sandwiched between the first and second mirror layers. A device according to the present invention comprising a resonant cavity light emitting diode (RCLED) mounted to a submount.
    Type: Grant
    Filed: May 18, 2004
    Date of Patent: February 19, 2008
    Assignee: Cree, Inc.
    Inventors: Shuji Nakamura, Steven DenBaars, John Edmond, Chuck Swoboda, Umesh Mishra
  • Publication number: 20080026502
    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: Application
    Filed: October 10, 2007
    Publication date: January 31, 2008
    Applicant: THE REGENTS OF THE UNIVERSITY OF CALIFORNIA
    Inventors: Bilge Imer, James Speck, Steven DenBaars
  • Publication number: 20070267654
    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: May 9, 2007
    Publication date: November 22, 2007
    Inventors: Arpan Chakraborty, Kwang-Choong Kim, James Speck, Steven DenBaars, Umesh Mishra
  • Publication number: 20070252164
    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: Application
    Filed: February 20, 2007
    Publication date: November 1, 2007
    Inventors: Hong Zhong, John Kaeding, Rajat Sharma, James Speck, Steven DenBaars, Shuji Nakamura
  • Publication number: 20070218655
    Abstract: A method for enhancing growth of device-quality planar semipolar nitride semiconductor thin films via metalorganic chemical vapor deposition (MOCVD) by using an (Al,In,Ga)N nucleation layer containing at least some indium. Specifically, the method comprises 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 19, 2007
    Publication date: September 20, 2007
    Inventors: Hitoshi Sato, John Kaeding, Michael Iza, Troy Baker, Benjamin Haskell, Steven DenBaars, Shuji Nakamura
  • Publication number: 20070218703
    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 19, 2007
    Publication date: September 20, 2007
    Inventors: John Kaeding, Dong-Seon Lee, Michael Iza, Troy Baker, Hitoshi Sato, Benjamin Haskell, James Speck, Steven DenBaars, Shuji Nakamura
  • Publication number: 20070190758
    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: February 9, 2007
    Publication date: August 16, 2007
    Applicant: The Regents of the University of California
    Inventors: John Kaeding, Hitoshi Sato, Michael Iza, Hirokuni Asamizu, Hong Zhong, Steven DenBaars, Shuji Nakamura
  • Publication number: 20070184637
    Abstract: A method of growing highly planar, fully transparent and specular m-plane gallium nitride (GaN) films. The method provides for a significant reduction in structural defect densities via a lateral overgrowth technique. High quality, uniform, thick m-plane GaN films are produced for use as substrates for polarization-free device growth.
    Type: Application
    Filed: April 6, 2007
    Publication date: August 9, 2007
    Applicant: THE REGENTS OF THE UNIVERSITY OF CALIFORNIA
    Inventors: Benjamin Haskell, Melvin McLaurin, Steven DenBaars, James Speck, Shuji Nakamura
  • Publication number: 20070145397
    Abstract: An (Al, Ga, In)N light emitting diode (LED), wherein light extraction from chip and/or phosphor conversion layer is optimized. By novel shaping of LED and package optics, a high efficiency light emitting diode is achieved.
    Type: Application
    Filed: December 8, 2006
    Publication date: June 28, 2007
    Inventors: Steven DenBaars, Shuji Nakamura, James Speck
  • Publication number: 20070128844
    Abstract: A method of fabricating non-polar a-plane GaN/(Al,B,In,Ga)N multiple quantum wells (MQWs). The a-plane MQWs are grown on the appropriate GaN/sapphire template layers via metalorganic chemical vapor deposition (MOCVD) with well widths ranging from 20 ? to 70 ?. The room temperature photoluminescence (PL) emission energy from the a-plane MQWs followed a square well trend modeled using self-consistent Poisson-Schrodinger (SCPS) calculations. Optimal PL emission intensity is obtained at a quantum well width of 52 ? for the a-plane MQWs.
    Type: Application
    Filed: December 11, 2003
    Publication date: June 7, 2007
    Inventors: Michael Craven, Steven DenBaars
  • Publication number: 20070126023
    Abstract: Lateral epitaxial overgrowth (LEO) of non-polar gallium nitride (GaN) films results in significantly reduced defect density.
    Type: Application
    Filed: February 1, 2007
    Publication date: June 7, 2007
    Applicant: THE REGENTS OF THE UNIVERSITY OF CALIFORNIA
    Inventors: Benjamin Haskell, Michael Craven, Paul Fini, Steven DenBaars, James Speck, Shuji Nakamura
  • Publication number: 20070120129
    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: Application
    Filed: February 13, 2006
    Publication date: May 31, 2007
    Inventors: Steven DenBaars, Eric Tarsa, Michael Mack, Bernd Keller, Brian Thibeault, Adam Saxler
  • Publication number: 20070111531
    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.
    Type: Application
    Filed: January 9, 2007
    Publication date: May 17, 2007
    Applicant: THE REGENTS OF THE UNIVERSITY OF CALIFORNIA
    Inventors: Troy Baker, Benjamin Haskell, Paul Fini, Steven DenBaars, James Speck, Shuji Nakamura