Patents by Inventor Christopher L. Chua

Christopher L. Chua 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: 20100197062
    Abstract: A method of fabricating a light emitting device includes modulating a crystal growth parameter to grow a quantum well layer that is inhomogeneous and that has a non-random composition fluctuation across the quantum well layer.
    Type: Application
    Filed: April 7, 2010
    Publication date: August 5, 2010
    Applicant: PALO ALTO RESEARCH CENTER INCORPORATED
    Inventors: CHRISTOPHER L. CHUA, ZHIHONG YANG, JOHN E. NORTHRUP, NOBLE MARSHALL JOHNSON
  • Publication number: 20100187695
    Abstract: A structure has at least one structure component formed of a first material residing on a substrate, such that the structure is out of a plane of the substrate. A first coating of a second material then coats the structure. A second coating of a non-oxidizing material coats the structure at a thickness less than a thickness of the second material.
    Type: Application
    Filed: March 26, 2010
    Publication date: July 29, 2010
    Applicant: PALO ALTO RESEARCH CENTER INCORPORATED
    Inventors: CHRISTOPHER L. CHUA, THOMAS HANTSCHEL, DAVID K. FORK, KOENRAAD F. VAN SCHUYLENBERGH, YAN YAN YANG
  • Patent number: 7764721
    Abstract: A method and structure for adjusting the wavelength output of a semiconductor device is described. In the method, the hydrogen concentration in an active region of the semiconductor device is adjusted either during fabrication or after the device has been fabricated. The adjustment provides a simple technique for fine tuning many device types including regular lasers and VCSEL structures. The adjustment also allows for mass production of lasers of many different frequencies on a single wafer substrate, a system particularly desirable for wavelength division multiplexing systems.
    Type: Grant
    Filed: December 15, 2005
    Date of Patent: July 27, 2010
    Assignee: Palo Alto Research Center Incorporated
    Inventors: Christopher L. Chua, Michael A. Kneissl, Noble M. Johnson, Peter Kiesel
  • Patent number: 7749782
    Abstract: An improved method of forming a LED with a roughened surface is described. Traditional methods of roughening a LED surface utilizes strong etchants that require sealing or protecting exposed areas of the LED. The described method uses a focused laser to separate the LED from the substrate, and a second laser to roughen the LED surface thereby avoiding the use of strong etchants. A mild etchant may be used on the laser roughened LED surface to remove unwanted metals.
    Type: Grant
    Filed: December 17, 2008
    Date of Patent: July 6, 2010
    Assignee: Palo Alto Research Center Incorporated
    Inventors: Clifford F Knollenberg, David P Bour, Christopher L Chua, Jeng Ping Lu
  • Publication number: 20100166032
    Abstract: A buried aperture in a nitride light emitting device is described. The aperture is formed in an aperture layer, typically an amorphous or polycrystalline material over an active layer that includes a nitride material. The aperture layer material typically also includes nitride. The aperture layer is etched to create an aperture which is filled with a conducting material by epitaxial regrowth. The amorphous layer is crystallized forming an electrically resistive material during or before regrowth. The conducting aperture in the electrically resistive material is well suited for directing current into a light emitting region of the active layer.
    Type: Application
    Filed: March 12, 2010
    Publication date: July 1, 2010
    Applicant: PALO ALTO RESEARCH CENTER INCORPORATED
    Inventors: Christopher L. Chua, Zhihong Yang
  • Publication number: 20100151602
    Abstract: An improved method of forming a LED with a roughened surface is described. Traditional methods of roughening a LED surface utilizes strong etchants that require sealing or protecting exposed areas of the LED. The described method uses a focused laser to separate the LED from the substrate, and a second laser to roughen the LED surface thereby avoiding the use of strong etchants. A mild etchant may be used on the laser roughened LED surface to remove unwanted metals.
    Type: Application
    Filed: December 17, 2008
    Publication date: June 17, 2010
    Applicant: Palo Alto Research Center Incorporated
    Inventors: Clifford F. Knollenberg, David P. Bour, Christopher L. Chua, Jeng Ping Lu
  • Publication number: 20100148146
    Abstract: An embodiment is a method and apparatus for a white or full-color light-emitting diode. First single or multiple quantum wells (QWs) at a first wavelength are formed at an active region between a p-type layer and an n-type layer of a light-emitting diode. Multiple passive quantum wells (QWs) are formed within the p-type layer or the n-type layer. The multiple passive QWs are optically pumped by the first or single multiple QWs to generate a desired color.
    Type: Application
    Filed: December 17, 2008
    Publication date: June 17, 2010
    Applicant: PALO ALTO RESEARCH CENTER INCORPORATED
    Inventors: David P. Bour, Christopher L. Chua, Noble M. Johnson
  • Publication number: 20100148147
    Abstract: An embodiment is a method and apparatus for a white or full-color light-emitting diode. A first mask having a first pattern is applied over surface of an n-type layer. A first active region is grown selectively and including single or multiple quantum wells (QWs) of a first active color to cause a first wavelength shift in a first vicinity area around the first pattern. The first wavelength shift results in an emission of a first desired color according to the first pattern.
    Type: Application
    Filed: December 17, 2008
    Publication date: June 17, 2010
    Applicant: Palo Alto Research Center Incorporated
    Inventors: David P. Bour, Christopher L. Chua, Noble M. Johnson
  • Publication number: 20100148188
    Abstract: An embodiment is a method and apparatus to induce flaw formation in nitride semiconductors. Regions of a thin film structure are selectively decomposed within a thin film layer at an interface with a substrate to form flaws in a pre-determined pattern within the thin film structure. The flaws locally concentrate stress in the pre-determined pattern during a stress-inducing operation. The stress-inducing operation is performed. The stress-inducing operation causes the thin film layer to fracture at the pre-determined pattern.
    Type: Application
    Filed: December 17, 2008
    Publication date: June 17, 2010
    Applicant: Palo Alto Research Center Incorporated
    Inventors: Clifford F. Knollenberg, William S. Wong, Christopher L. Chua
  • Publication number: 20100148197
    Abstract: A method of texturing a surface within or immediately adjacent to a template layer of a LED is described. The method uses a texturing laser directed through a substrate to decompose and pit a semiconductor material at the surface to be textured. By texturing the surface, light trapping within the template layer is reduced. Furthermore, by patterning the arrangement of pits, metal coating each pit can be arranged to spread current through the template layer and thus through the n-doped region of a LED.
    Type: Application
    Filed: December 17, 2008
    Publication date: June 17, 2010
    Applicant: Palo Alto Research Center Incorporated
    Inventors: David P. Bour, Clifford F. Knollenberg, Christopher L. Chua
  • Patent number: 7733397
    Abstract: A method of making a curved sensor is described. The method involves projecting portions of a curved three dimensional structure such as a hemisphere onto a two dimensional substrate in an outline pattern. The outline pattern typically serves as a perimeter of a sensor. After forming a sensor in the shape of the outline pattern, the two dimensional substrate is flexed to form a three dimensional sensor structure.
    Type: Grant
    Filed: December 22, 2006
    Date of Patent: June 8, 2010
    Assignee: Palo Alto Research Center Incorporated
    Inventors: Jeng Ping Lu, Christopher L. Chua
  • Publication number: 20100127236
    Abstract: A semiconductor laser diode with a high indium content is provided with a lattice matched cladding layer or layers. One or both of the cladding layers may comprise bulk aluminum gallium indium nitride in the ratio of AlxGa1-x-yInyN and/or a short period superlattice structures of, for example, a plurality of alternating layer pairs of aluminum gallium indium nitride in the ratio of AlxGa1-x-yInyN and gallium indium nitride in the ratio of GasIn1-sN, providing a multi-quantum barrier (MQB) effect. Lattice matching of the cladding layer(s) and active layer reduce or eliminate strain, and the materials chosen for the cladding layers optimizes optical and carrier confinement. Alternatively, the lattice parameters may be selected to provide strain balanced MQBs, e.g., where the barrier layers are tensile-strained and the well layers compressed.
    Type: Application
    Filed: November 21, 2008
    Publication date: May 27, 2010
    Applicant: PALO ALTO RESEARCH CENTER INCORPORATED
    Inventors: David P. Bour, Christopher L. Chua, Noble M. Johnson, Zhihong Yang
  • Patent number: 7723719
    Abstract: A method of fabricating a light emitting device includes modulating a crystal growth parameter to grow a quantum well layer that is inhomogeneous and that has a non-random composition fluctuation across the quantum well layer.
    Type: Grant
    Filed: December 14, 2007
    Date of Patent: May 25, 2010
    Assignee: Palo Alto Research Center Incorporated
    Inventors: Christopher L. Chua, Zhihong Yang, John E. Northrup, Noble Marshall Johnson
  • Patent number: 7718455
    Abstract: A method of forming a buried aperture in a nitride light emitting device is described. The method involves forming an aperture layer, typically an amorphous or polycrystalline material over an active layer that includes a nitride material. The aperture layer material typically also includes nitride. The aperture layer is etched to create an aperture which is then filled with a conducting material by epitaxial regrowth. The amorphous layer is crystallized forming an electrically resistive material during or before regrowth. The conducting aperture in the electrically resistive material is well suited for directing current into a light emitting region of the active layer.
    Type: Grant
    Filed: December 17, 2007
    Date of Patent: May 18, 2010
    Assignee: Palo Alto Research Center Incorporated
    Inventors: Christopher L. Chua, Zhihong Yang
  • Patent number: 7714340
    Abstract: A bottom-emitting nitride light-emitting device with enhanced light extraction efficiency is provided. The increased light output is provided by the reflector that redirects upward-going light towards the bottom output. A mesh contact area, in one form, spreads current across the entire carrier injection area without occupying the entire top surface of the device.
    Type: Grant
    Filed: September 6, 2006
    Date of Patent: May 11, 2010
    Assignee: Palo Alto Research Center Incorporated
    Inventors: Christopher L. Chua, Zhihong Yang, Noble M. Johnson, Mark R. Teepe
  • Patent number: 7713388
    Abstract: A structure has at least one structure component formed of a first material residing on a substrate, such that the structure is out of a plane of the substrate. A first coating of a second material then coats the structure. A second coating of a non-oxidizing material coats the structure at a thickness less than a thickness of the second material.
    Type: Grant
    Filed: February 27, 2006
    Date of Patent: May 11, 2010
    Assignee: Palo Alto Research Center Incorporated
    Inventors: Christopher L. Chua, Thomas Hantschel, David K. Fork, Koenraad F. Van Schuylenbergh, Yan Yan Yang
  • Patent number: 7688876
    Abstract: A Vertical Cavity Surface Emitting Laser (VCSEL) assembly including a VCSEL structure having a light-emitting region located on its surface, a relatively wettable region of a surface modifier coating formed over the light emitting region, and a microlens formed on the relatively wettable region. A relatively non-wettable region of the surface modifier coating is formed around the light-emitting region (e.g., on the electrode surrounding the light-emitting region). The surface modifier coating is formed, for example, from one or more organothiols that change the surface energies of the light-emitting region and/or the electrode to facilitate self-assembly and self-registration of the microlens material. The microlens material is printed, microjetted, or dip coated onto the VCSEL structure such that the microlens material wets to the relatively wettable region, thereby forming a liquid bead that is reliably positioned over the light-emitting region. The liquid bead is then cured to form the microlens.
    Type: Grant
    Filed: December 11, 2007
    Date of Patent: March 30, 2010
    Assignee: Palo Alto Research Center Incorporated
    Inventors: Michael L. Chabinyc, Patrick Y. Maeda, Christopher L. Chua
  • Publication number: 20100074292
    Abstract: The AlGaN upper cladding layer of a nitride laser diode is replaced by a non-epitaxial layer, such as metallic silver. If chosen to have a relatively low refractive index value, the mode loss from absorption in the non-epitaxial cladding layer is acceptably small. If also chosen to have a relatively high work-function, the non-epitaxial layer forms an electrical contact to the nitride semiconductors. An indium-tin-oxide layer may also be employed with the non-epitaxial cladding layer.
    Type: Application
    Filed: September 24, 2008
    Publication date: March 25, 2010
    Applicant: Palo Alto Research Center Incorporated
    Inventors: David P. Bour, Christopher L. Chua, Noble M. Johnson, Zhihong Yang
  • Publication number: 20100063753
    Abstract: One disclosed feature of the embodiments is a control processor in a vapor delivery system for chemical vapor deposition precursors. A pressurization rate processor calculates first and second pressurization rate curves at first and second time instants. A volume calculator computes consumed volume based on first and second volumes at the respective first and second time instants. The first and second volumes are computed using slopes of lines fitting the first and second pressurization rate curves.
    Type: Application
    Filed: September 10, 2008
    Publication date: March 11, 2010
    Applicant: Palo Alto Research Center Incorporated
    Inventors: David P. Bour, Christopher L. Chua, Zhihong Yang
  • Publication number: 20100006023
    Abstract: Nitride semiconductor films, such as for use in solid state light emitting devices and electronic devices, are fabricated in an environment of relatively high nitrogen potential such that nitrogen vacancies in the growing film are reduced. A reactor design, and method for its use, provide high nitrogen precursor partial pressure, precracking of the precursor using a catalytic metal surface, prepyrolyzing the precursor, using catalytically-cracked molecular nitrogen as a nitrogen precursor, and/or exposing the surface to an ambient which is extremely rich in active nitrogen species. Improved efficiency for light emitting devices, particularly in the blue and green wavelengths and improve transport properties in nitride electronic devices, i.e., improved performance from nitride-based devices such as InGaAlN laser diodes, transistors, and light emitting diodes is thereby provided.
    Type: Application
    Filed: July 11, 2008
    Publication date: January 14, 2010
    Applicant: PALO ALTO RESEARCH CENTER INCORPORATED
    Inventors: David P. Bour, Peter Kiesel, Christopher L. Chua, Noble M. Johnson, Zhihong Yang, John E. Northrup