Patents by Inventor Xiao Gordon Liu

Xiao Gordon Liu 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: 6896729
    Abstract: Group III-V, II-VI and related monocrystalline compounds are grown with a rigid support of a sealed ampoule, carbon doping and resistivity control, and thermal gradient control in a crystal growth furnace. A support cylinder provides structural support for the combined sealed ampoule crucible assembly, while low-density insulating material inside the support cylinder deters convection and conduction heating. Radiation channels penetrating the low-density material provide pathways for radiation heating into and out of the seed well and transition regions of the crystal growth crucible. A hollow core in the insulation material directly beneath the seed well provides cooling in the center of the growing crystal, which enables uniform, level growth of the crystal ingot and a flat crystal-melt interface which results in crystal wafers with uniform electrical properties.
    Type: Grant
    Filed: July 3, 2002
    Date of Patent: May 24, 2005
    Assignee: AXT, Inc.
    Inventors: Xiao Gordon Liu, Wei Guo Liu
  • Publication number: 20040173140
    Abstract: An apparatus and a method for growth of Group III-V monocrystalline semiconductor compounds in a closed system with a balanced pressure maintained between the inside of a sealed ampoule and a pressure vessel. The vapor pressure inside the sealed ampoule can be controlled by temperature, the amount of polycrystalline charge and an amount of material such as phosphorus inside the sealed ampoule. Filling and release of an inert gas is used to control the pressure in the pressure vessel.
    Type: Application
    Filed: March 5, 2003
    Publication date: September 9, 2004
    Inventors: Xiao Gordon Liu, Morris Young
  • Publication number: 20030172870
    Abstract: An apparatus for producing large diameter monocrystalline Group III-V, II-VI compounds that have reduced crystal defect density, improved crystal growth yield, and improved bulk material characteristics. The apparatus comprises a crucible or boat, an ampoule that contains the crucible or boat, a heating unit disposed about the ampoule, and a liner disposed between the heating unit and the ampoule. The liner is preferably composed of a quartz material. When the liner and the ampoule are made of the same material, such as quartz, the thermal expansion coefficients of the liner and ampoule are the same, which significantly increases the lifetime of the liner and the single-crystal yield.
    Type: Application
    Filed: March 14, 2002
    Publication date: September 18, 2003
    Applicant: AXT, Inc.
    Inventors: Xiao Gordon Liu, Weiguo Liu
  • Publication number: 20030037721
    Abstract: Group III-V, II-VI and related monocrystalline compounds are grown with a rigid support of a sealed ampoule, carbon doping and resistivity control, and thermal gradient control in a crystal growth furnace. A support cylinder provides structural support for the combined sealed ampoule crucible assembly, while low-density insulating material inside the support cylinder deters convection and conduction heating. Radiation channels penetrating the low-density material provide pathways for radiation heating into and out of the seed well and transition regions of the crystal growth crucible. A hollow core in the insulation material directly beneath the seed well provides cooling in the center of the growing crystal, which enables uniform, level growth of the crystal ingot and a flat crystal-melt interface which results in crystal wafers with uniform electrical properties.
    Type: Application
    Filed: July 3, 2002
    Publication date: February 27, 2003
    Inventors: Xiao Gordon Liu, Wei Guo Liu