Patents by Inventor Robert F. Davis

Robert F. Davis 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: 7338707
    Abstract: Laminates of having a first outer layer of weatherable film, at least one mid layer, and a second outer layer containing an opacifying quantity of white pigment. The laminates are particularly useful for protecting photovoltaic cells, solar panels, and circuit boards. In photovoltaic cells, the laminates result in increased power generation.
    Type: Grant
    Filed: June 13, 2006
    Date of Patent: March 4, 2008
    Assignee: Madico, Inc.
    Inventors: Carl P. Kernander, Robert F Davis, Frank A. Mannarino, Marina Temchenko
  • Patent number: 7217641
    Abstract: More specifically, gallium nitride semiconductor layers may be fabricated by etching an underlying gallium nitride layer on a sapphire substrate, to define at least one post in the underlying gallium nitride layer and at least one trench in the underlying gallium nitride layer. The at least one post includes a gallium nitride top and a gallium nitride sidewall. The at least one trench includes a trench floor. The gallium nitride sidewalls are laterally grown into the at least one trench, to thereby form a gallium nitride semiconductor layer. However, prior to performing the laterally growing step, the sapphire substrate and/or the underlying gallium nitride layer is treated to prevent growth of gallium nitride from the trench floor from interfering with the lateral growth of the gallium nitride sidewalls of the at least one post into the at least one trench.
    Type: Grant
    Filed: January 23, 2004
    Date of Patent: May 15, 2007
    Assignee: North Carolina State University
    Inventors: Thomas Gehrke, Kevin J. Linthicum, Robert F. Davis
  • Patent number: 7195993
    Abstract: A gallium nitride layer is laterally grown into a trench in the gallium nitride layer, to thereby form a lateral gallium nitride semiconductor layer. At least one microelectronic device may then be formed in the lateral gallium nitride semiconductor layer. Dislocation defects do not significantly propagate laterally into the lateral gallium nitride semiconductor layer, so that the lateral gallium nitride semiconductor layer is relatively defect free.
    Type: Grant
    Filed: August 10, 2004
    Date of Patent: March 27, 2007
    Assignee: North Carolina State University
    Inventors: Tsvetanka Zheleva, Darren B. Thomson, Scott A. Smith, Kevin J. Linthicum, Thomas Gehrke, Robert F. Davis
  • Patent number: 7095062
    Abstract: A substrate includes non-gallium nitride posts that define trenches therebetween, wherein the non-gallium nitride posts include non-gallium nitride sidewalls and non-gallium nitride tops and the trenches include non-gallium floors. Gallium nitride is grown on the non-gallium nitride posts, including on the non-gallium nitride tops. Preferably, gallium nitride pyramids are grown on the non-gallium nitride tops and gallium nitride then is grown on the gallium nitride pyramids. The gallium nitride pyramids preferably are grown at a first temperature and the gallium nitride preferably is grown on the pyramids at a second temperature that is higher than the first temperature. The first temperature preferably is about 1000° C. or less and the second temperature preferably is about 1100° C. or more. However, other than temperature, the same processing conditions preferably are used for both growth steps. The grown gallium nitride on the pyramids preferably coalesces to form a continuous gallium nitride layer.
    Type: Grant
    Filed: March 8, 2005
    Date of Patent: August 22, 2006
    Assignee: North Carolina State University
    Inventors: Kevin J. Linthicum, Thomas Gehrke, Robert F. Davis
  • Patent number: 6897483
    Abstract: A gallium nitride layer is laterally grown into a trench in the gallium nitride layer, to thereby form a lateral gallium nitride semiconductor layer. At least one microelectronic device may then be formed in the lateral gallium nitride semiconductor layer. Dislocation defects do not significantly propagate laterally into the lateral gallium nitride semiconductor layer, so that the lateral gallium nitride semiconductor layer is relatively defect free.
    Type: Grant
    Filed: April 30, 2003
    Date of Patent: May 24, 2005
    Assignee: North Carolina State University
    Inventors: Tsvetanka Zheleva, Darren B. Thomson, Scott A. Smith, Kevin J. Linthicum, Thomas Gehrke, Robert F. Davis
  • Patent number: 6864160
    Abstract: A substrate includes non-gallium nitride posts that define trenches therebetween, wherein the non-gallium nitride posts include non-gallium nitride sidewalls and non-gallium nitride tops and the trenches include non-gallium floors. Gallium nitride is grown on the non-gallium nitride posts, including on the non-gallium nitride tops. Preferably, gallium nitride pyramids are grown on the non-gallium nitride tops and gallium nitride then is grown on the gallium nitride pyramids. The gallium nitride pyramids preferably are grown at a first temperature and the gallium nitride preferably is grown on the pyramids at a second temperature that is higher than the first temperature. The first temperature preferably is about 1000° C. or less and the second temperature preferably is about 1100° C. or more. However, other than temperature, the same processing conditions preferably are used for both growth steps. The grown gallium nitride on the pyramids preferably coalesces to form a continuous gallium nitride layer.
    Type: Grant
    Filed: April 3, 2002
    Date of Patent: March 8, 2005
    Assignee: North Carolina State University
    Inventors: Kevin J. Linthicum, Thomas Gehrke, Robert F. Davis
  • Publication number: 20040202866
    Abstract: Laminates of having a first outer layer of weatherable film, at least one mid layer, and a second outer layer of ethylene vinyl acetate containing an opacifying quantity of white pigment. The laminates are particularly useful for protecting photovoltaic cells, solar panels, and circuit boards. In photovolteic cells, the laminates result in increased power generation.
    Type: Application
    Filed: April 11, 2003
    Publication date: October 14, 2004
    Inventors: Carl P. Kernander, Robert F. Davis, Frank A. Mannarino
  • Publication number: 20040152321
    Abstract: More specifically, gallium nitride semiconductor layers may be fabricated by etching an underlying gallium nitride layer on a sapphire substrate, to define at least one post in the underlying gallium nitride layer and at least one trench in the underlying gallium nitride layer. The at least one post includes a gallium nitride top and a gallium nitride sidewall. The at least one trench includes a trench floor. The gallium nitride sidewalls are laterally grown into the at least one trench, to thereby form a gallium nitride semiconductor layer. However, prior to performing the laterally growing step, the sapphire substrate and/or the underlying gallium nitride layer is treated to prevent growth of gallium nitride from the trench floor from interfering with the lateral growth of the gallium nitride sidewalls of the at least one post into the at least one trench.
    Type: Application
    Filed: January 23, 2004
    Publication date: August 5, 2004
    Inventors: Thomas Gehrke, Kevin J. Linthicum, Robert F. Davis
  • Publication number: 20040029365
    Abstract: A gallium nitride microelectronic layer is fabricated by converting a surface of a (111) silicon layer to 3C-silicon carbide. A layer of 3C-silicon carbide is then epitaxially grown on the converted surface of the (111) silicon layer. A layer of 2H-gallium nitride then is grown on the epitaxially grown layer of 3C-silicon carbide. The layer of 2H-gallium nitride then is laterally grown to produce the gallium nitride microelectronic layer. In one embodiment, the silicon layer is a (111) silicon substrate, the surface of which is converted to 3C-silicon carbide. In another embodiment, the (111) silicon layer is part of a Separation by IMplanted OXygen (SIMOX) silicon substrate which includes a layer of implanted oxygen that defines the (111) layer on the (111) silicon substrate. In yet another embodiment, the (111) silicon layer is a portion of a Silicon-On-Insulator (SOI) substrate in which a (111) silicon layer is bonded to a substrate.
    Type: Application
    Filed: August 4, 2003
    Publication date: February 12, 2004
    Inventors: Kevin J. Linthicum, Thomas Gehrke, Robert F. Davis, Darren B. Thomson, Kieran M. Tracy
  • Patent number: 6686261
    Abstract: More specifically, gallium nitride semiconductor layers may be fabricated by etching an underlying gallium nitride layer on a sapphire substrate, to define at least one post in the underlying gallium nitride layer and at least one trench in the underlying gallium nitride layer. The at least one post includes a gallium nitride top and a gallium nitride sidewall. The at least one trench includes a trench floor. The gallium nitride sidewalls are laterally grown into the at least one trench, to thereby form a gallium nitride semiconductor layer. However, prior to performing the laterally growing step, the sapphire substrate and/or the underlying gallium nitride layer is treated to prevent growth of gallium nitride from the trench floor from interfering with the lateral growth of the gallium nitride sidewalls of the at least one post into the at least one trench.
    Type: Grant
    Filed: April 1, 2003
    Date of Patent: February 3, 2004
    Assignee: North Carolina State University
    Inventors: Thomas Gehrke, Kevin J. Linthicum, Robert F. Davis
  • Publication number: 20030207551
    Abstract: More specifically, gallium nitride semiconductor layers may be fabricated by etching an underlying gallium nitride layer on a sapphire substrate, to define at least one post in the underlying gallium nitride layer and at least one trench in the underlying gallium nitride layer. The at least one post includes a gallium nitride top and a gallium nitride sidewall. The at least one trench includes a trench floor. The gallium nitride sidewalls are laterally grown into the at least one trench, to thereby form a gallium nitride semiconductor layer. However, prior to performing the laterally growing step, the sapphire substrate and/or the underlying gallium nitride layer is treated to prevent growth of gallium nitride from the trench floor from interfering with the lateral growth of the gallium nitride sidewalls of the at least one post into the at least one trench.
    Type: Application
    Filed: April 1, 2003
    Publication date: November 6, 2003
    Inventors: Thomas Gehrke, Kevin J. Linthicum, Robert F. Davis
  • Publication number: 20030194828
    Abstract: A gallium nitride layer is laterally grown into a trench in the gallium nitride layer, to thereby form a lateral gallium nitride semiconductor layer. At least one microelectronic device may then be formed in the lateral gallium nitride semiconductor layer. Dislocation defects do not significantly propagate laterally into the lateral gallium nitride semiconductor layer, so that the lateral gallium nitride semiconductor layer is relatively defect free.
    Type: Application
    Filed: April 30, 2003
    Publication date: October 16, 2003
    Inventors: Tsvetanka Zheleva, Darren B. Thomson, Scott A. Smith, Kevin J. Linthicum, Thomas Gehrke, Robert F. Davis
  • Patent number: 6621148
    Abstract: A substrate includes non-gallium nitride posts that define trenches therebetween, wherein the non-gallium nitride posts include non-gallium nitride sidewalls and non-gallium nitride tops and the trenches include non-gallium floors. Gallium nitride is grown on the non-gallium nitride posts, including on the non-gallium nitride tops. Preferably, gallium nitride pyramids are grown on the non-gallium nitride tops and gallium nitride then is grown on the gallium nitride pyramids. The gallium nitride pyramids preferably are grown at a first temperature and the gallium nitride preferably is grown on the pyramids at a second temperature that is higher than the first temperature. The first temperature preferably is about 1000° C. or less and the second temperature preferably is about 1100° C. or more. However, other than temperature, the same processing conditions preferably are used for both growth steps.
    Type: Grant
    Filed: October 9, 2001
    Date of Patent: September 16, 2003
    Assignee: North Carolina State University
    Inventors: Kevin J. Linthicum, Thomas Gehrke, Robert F. Davis
  • Patent number: 6608327
    Abstract: A gallium nitride semiconductor layer is fabricated by masking an underlying gallium nitride layer with a first mask that includes a first array of openings therein and growing the underlying gallium nitride layer through the first array of openings and onto the first mask, to thereby form a first overgrown gallium nitride semiconductor layer. The first overgrown layer is then masked with the second mask that includes a second array of openings therein. The second array of openings is laterally offset from the first array of openings. The first overgrown gallium nitride layer is then grown through the second array of openings and onto the second mask, to thereby form a second overgrown gallium nitride semiconductor layer. Microelectronic devices may then be formed in the second overgrown gallium nitride semiconductor layer.
    Type: Grant
    Filed: February 27, 1998
    Date of Patent: August 19, 2003
    Assignee: North Carolina State University
    Inventors: Robert F. Davis, Ok-Hyun Nam
  • Patent number: 6602764
    Abstract: A gallium nitride microelectronic layer is fabricated by converting a surface of a (111) silicon layer to 3C-silicon carbide. A layer of 3C-silicon carbide is then epitaxially grown on the converted surface of the (111) silicon layer. A layer of 2H-gallium nitride then is grown on the epitaxially grown layer of 3C-silicon carbide. The layer of 2H-gallium nitride then is laterally grown to produce the gallium nitride microelectronic layer. The silicon layer is a (111) silicon substrate, the surface of which is converted to 3C-silicon carbide, or the (111) silicon layer is part of a Separation by IMplanted OXygen (SIMOX) silicon substrate which includes a layer of implanted oxygen that defines the (111) layer on the (111) silicon substrate, or the (111) silicon layer is a portion of a Silicon-On-Insulator (SOI) substrate in which a (111) silicon layer is bonded to a substrate.
    Type: Grant
    Filed: May 7, 2001
    Date of Patent: August 5, 2003
    Assignee: North Carolina State University
    Inventors: Kevin J. Linthicum, Thomas Gehrke, Robert F. Davis, Darren B. Thomson, Kieran M. Tracy
  • Patent number: 6602763
    Abstract: A gallium nitride semiconductor layer is fabricated by masking an underlying gallium nitride layer with a mask that includes an array of openings therein, and growing the underlying gallium nitride layer through the array of openings and onto the mask, to thereby form an overgrown gallium nitride semiconductor layer. Although dislocation defects may propagate vertically from the underlying gallium nitride layer to the grown gallium nitride layer through the mask openings, the overgrown gallium nitride layer is relatively defect free. The overgrown gallium nitride semiconductor layer may be overgrown until the overgrown gallium nitride layer coalesces on the mask, to form a continuous overgrown monocrystalline gallium nitride semiconductor layer. The gallium nitride semiconductor layer may be grown using metalorganic vapor phase epitaxy. Microelectronic devices may be formed in the overgrown gallium nitride semiconductor layer.
    Type: Grant
    Filed: February 9, 2001
    Date of Patent: August 5, 2003
    Assignee: North Carolina State University
    Inventors: Robert F. Davis, Ok-Hyun Nam, Tsvetanka Zheleva, Michael D. Bremser
  • Patent number: 6586778
    Abstract: A gallium nitride layer is pendeoepitaxially grown on weak posts on a substrate that are configured to crack due to a thermal expansion coefficient mismatch between the substrate and the gallium nitride layer on the weak posts. Thus, upon cooling, at least some of the weak posts crack, to thereby relieve stress in the gallium nitride semiconductor layer. Accordingly, low defect density gallium nitride semiconductor layers may be produced. Moreover, the weak posts can allow relatively easy separation of the substrate from the gallium nitride semiconductor layer to provide a freestanding gallium nitride layer. The weak posts may be formed by forming an array of posts in spaced apart staggered relation on the substrate. By staggering the posts, later fracturing may be promoted compared to long unstaggered posts. Alternatively, the posts may have a height to width ratio in excess of 0.5, so that the relatively narrow posts promote cracking upon reduction of the temperature.
    Type: Grant
    Filed: April 4, 2002
    Date of Patent: July 1, 2003
    Assignee: North Carolina State University
    Inventors: Kevin J. Linthicum, Thomas Gehrke, Robert F. Davis
  • Patent number: 6570192
    Abstract: A gallium nitride semiconductor layer is fabricated by masking an underlying gallium nitride layer with a mask that includes an array of openings therein, and growing the underlying gallium nitride layer through the array of openings and onto the mask, to thereby form an overgrown gallium nitride semiconductor layer. Although dislocation defects may propagate vertically from the underlying gallium nitride layer to the grown gallium nitride layer through the mask openings, the overgrown gallium nitride layer is relatively defect free. The overgrown gallium nitride semiconductor layer may be overgrown until the overgrown gallium nitride layer coalesces on the mask, to form a continuous overgrown monocrystalline gallium nitride semiconductor layer. The gallium nitride semiconductor layer may be grown using metalorganic vapor phase epitaxy. Microelectronic devices may be formed in the overgrown gallium nitride semiconductor layer.
    Type: Grant
    Filed: March 14, 2000
    Date of Patent: May 27, 2003
    Assignee: North Carolina State University
    Inventors: Robert F. Davis, Ok-Hyun Nam, Tsvetanka Zheleva, Michael D. Bremser
  • Patent number: 6545300
    Abstract: More specifically, gallium nitride semiconductor layers may be fabricated by etching an underlying gallium nitride layer on a sapphire substrate, to define at least one post in the underlying gallium nitride layer and at least one trench in the underlying gallium nitride layer. The at least one post includes a gallium nitride top and a gallium nitride sidewall. The at least one trench includes a trench floor. The gallium nitride sidewalls are laterally grown into the at least one trench, to thereby form a gallium nitride semiconductor layer. However, prior to performing the laterally growing step, the sapphire substrate and/or the underlying gallium nitride layer is treated to prevent growth of gallium nitride from the trench floor from interfering with the lateral growth of the gallium nitride sidewalls of the at least one post into the at least one trench.
    Type: Grant
    Filed: July 3, 2001
    Date of Patent: April 8, 2003
    Assignee: North Carolina State University
    Inventors: Thomas Gehrke, Kevin J. Linthicum, Robert F. Davis
  • Patent number: 6521514
    Abstract: More specifically, gallium nitride semiconductor layers may be fabricated by etching an underlying gallium nitride layer on a sapphire substrate, to define at least one post in the underlying gallium nitride layer and at least one trench in the underlying gallium nitride layer. The at least one post includes a gallium nitride top and a gallium nitride sidewall. The at least one trench includes a trench floor. The gallium nitride sidewalls are laterally grown into the at least one trench, to thereby form a gallium nitride semiconductor layer. However, prior to performing the laterally growing step, the sapphire substrate and/or the underlying gallium nitride layer is treated to prevent growth of gallium nitride from the trench floor from interfering with the lateral growth of the gallium nitride sidewalls of the at least one post into the at least one trench.
    Type: Grant
    Filed: November 17, 1999
    Date of Patent: February 18, 2003
    Assignee: North Carolina State University
    Inventors: Thomas Gehrke, Kevin J. Linthicum, Robert F. Davis