Patents by Inventor H. McDonald Hobgood

H. McDonald Hobgood 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: 5985024
    Abstract: Method and apparatus for growing semiconductor grade silicon carbide boules (84). Pure silicon feedstock (36) is melted and vaporized. The vaporized silicon is reacted with a high purity carbon-containing gas (64), such as propane, and the gaseous species resulting from the reaction are deposited on a silicon carbide seed crystal (50), resulting in the growth of monocrystalline silicon carbide.
    Type: Grant
    Filed: December 11, 1997
    Date of Patent: November 16, 1999
    Assignee: Northrop Grumman Corporation
    Inventors: Vijay Balakrishna, R. Noel Thomas, Godfrey Augustine, Richard H. Hopkins, H. McDonald Hobgood
  • Patent number: 5873937
    Abstract: A method of growing 4-H polytype silicon carbide crystals in a physical vapor transport system where the surface temperature of the crystal is maintained at less than about C. and the pressure inside the PVT system is decreased to compensate for the lower growth temperature.
    Type: Grant
    Filed: May 5, 1997
    Date of Patent: February 23, 1999
    Assignee: Northrop Grumman Corporation
    Inventors: Richard H. Hopkins, Godfrey Augustine, H. McDonald Hobgood