Patents by Inventor Francis K. Chai

Francis K. Chai 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: 8519410
    Abstract: A vertical-sidewall dual-mesa static induction transistor (SIT) structure includes a silicon carbide substrate having a layer arrangement formed thereon. Laterally spaced ion implanted gate regions are defined in the layer arrangement. Source regions are defined in the layer arrangement. Each of the source regions can include a channel mesa having a source mesa disposed thereon. The source mesa includes upright sidewalls relative to a principal plane of the substrate defining a horizontal dimension thereof. The channel mesa includes upright sidewalls relative to the source mesa and the principal plane of the substrate. Also disclosed is a method of fabricating a vertical-sidewall dual-mesa SiC transistor device. The method includes implanting ions at an angle relative to a principal plane of the substrate to form gate junctions in upper portions of the substrate and lateral portions of the upright channel mesas.
    Type: Grant
    Filed: December 13, 2011
    Date of Patent: August 27, 2013
    Assignee: Microsemi Corporation
    Inventors: Bruce Odekirk, Francis K. Chai, Edward William Maxwell, Douglas C. Thompson, Jr.
  • Publication number: 20110049532
    Abstract: A dual-mesa static induction transistor (SIT) structure includes a silicon carbide substrate having a layer arrangement formed thereon. Laterally spaced ion implanted gate regions are defined in the layer arrangement. Source regions are defined in the layer arrangement. Each of the source regions can include a channel mesa having a source mesa disposed thereon. The source mesa includes sidewalls relative to a principal plane of the substrate defining a horizontal dimension thereof. The channel mesa includes slanted sidewalls relative to the source mesa and the principal plane of the substrate. Also disclosed is a method of fabricating a dual-mesa SiC transistor device. The method includes implanting ions at a normal relative to a principal plane of the substrate to form gate junctions in upper portions of the substrate and lateral portions of the slanted channel mesas.
    Type: Application
    Filed: August 27, 2010
    Publication date: March 3, 2011
    Applicant: MICROSEMI CORPORATION
    Inventors: Bruce Odekirk, Francis K. Chai, Edward W. Maxwell
  • Patent number: 6551869
    Abstract: A lateral PNP is disclosed in which a substrate of a first conductivity type is used. On top of the substrate a buried region of a second conductivity type is formed. A lightly doped collector region is located above the buried region. The lateral PNP also includes a base region of a second conductivity type formed by a graded channel implant and a well region of a second conductivity type, the well region contacting the base region, the buried region and a base contact. Additionally, there are collector contacts and emitter contacts of a first conductivity type. The lightly doped collector region results in a large Early voltage and the base region provides for a high current gain.
    Type: Grant
    Filed: June 9, 2000
    Date of Patent: April 22, 2003
    Assignee: Motorola, Inc.
    Inventors: Francis K. Chai, Vida Ilderem Burger, Carl S. Kyono, Sharanda L. Bigelow, Rainer Thoma