Patents by Inventor Janna Ruth Duvall

Janna Ruth Duvall 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).

  • Ohmic contacts for high electron mobility transistors and a method of making the same
    Patent number: 6852615
    Abstract: A process and related product in which ohmic contacts are formed in High Electron Mobility Transistors (HEMTs) employing compound substrates such as gallium nitride. An improved device and an improvement to a process for fabrication of ohmic contacts to GaN/AlGaN HEMTs using a novel two step resist process to fabricate the ohmic contacts are described. This novel two-step process consists of depositing a plurality of layers having compounds of Group III V elements on a substrate; patterning and depositing a first photoresist on one of the layers; etching recessed areas into this layer; depositing ohmic metals on the recessed areas; removing the first photoresist; patterning and depositing a second photoresist, smaller in profile than the first photoresist, on the layer; depositing more ohmic metal on the layer allowing for complete coverage of the recessed areas; removing the second photoresist, and annealing the semiconductor structure.
    Type: Grant
    Filed: June 9, 2003
    Date of Patent: February 8, 2005
    Assignee: HRL Laboratories, LLC
    Inventors: Miroslav Micovic, Tahir Hussain, Paul Hashimoto, Janna Ruth Duvall
  • Ohmic contacts for high electron mobility transistors and a method of making the same
    Publication number: 20030227027
    Abstract: A process and related product in which ohmic contacts are formed in High Electron Mobility Transistors (HEMTs) employing compound substrates such as gallium nitride. An improved device and an improvement to a process for fabrication of ohmic contacts to GaN/AlGaN HEMTs using a novel two step resist process to fabricate the ohmic contacts are described. This novel two-step process consists of depositing a plurality of layers having compounds of Group III V elements on a substrate; patterning and depositing a first photoresist on one of the layers; etching recessed areas into this layer; depositing ohmic metals on the recessed areas; removing the first photoresist; patterning and depositing a second photoresist, smaller in profile than the first photoresist, on the layer; depositing more ohmic metal on the layer allowing for complete coverage of the recessed areas; removing the second photoresist, and annealing the semiconductor structure.
    Type: Application
    Filed: June 9, 2003
    Publication date: December 11, 2003
    Applicant: HRL Laboratories, LLC
    Inventors: Miroslav Micovic, Tahir Hussain, Paul Hashimoto, Janna Ruth Duvall