Patents by Inventor Karl R. Hofmann

Karl R. Hofmann 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).

  • Modulation doped high electron mobility transistor with n-i-p-i structure
    Patent number: 4855797
    Abstract: A modulation-doped field effect transistor includes an undoped semiconductor layer and an arrangement for supplying charge carriers into a region of the semiconductor layer adjacent one side. An arrangement is provided for locally modulating hole and electron density in another region adjacent the other side of the semiconductor layer in a repeating pattern of alternations so as to inhibit current flow in the direction of the alternations.
    Type: Grant
    Filed: July 6, 1987
    Date of Patent: August 8, 1989
    Assignee: Siemens Corporate Research and Support, Inc.
    Inventors: Erhard Kohn, Karl R. Hofmann