Patents by Inventor Muni M. Mitchell

Muni M. Mitchell 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: 5010023
    Abstract: A rectifier is fabricated from a P-N junction having a P-type semiconductor layer and an adjacent N-type semiconductor layer. A mesa structure is formed in at least one of said layers. Impurities are deposited at the top of the mesa to form a high concentration region in the surface thereof. The impurities are diffused from the top surface of the mesa toward the P-N junction, whereby the mesa geometry causes the diffusion to take on a generally concave shape as it penetrates into the mesa. The distance between the perimeter of the high concentration region and the wafer substrate is therefore greater than the distance between the central portion of said region and the wafer substrate, providing improved breakdown voltage characteristics and a lower surface field. Breakdown voltage can be measured during device fabrication and precisely controlled by additional diffusions to drive the high concentration region to the required depth.
    Type: Grant
    Filed: September 27, 1989
    Date of Patent: April 23, 1991
    Assignee: General Instrument Corporation
    Inventors: Willem G. Einthoven, Muni M. Mitchell
  • Patent number: 5008735
    Abstract: The invention is a packaged diode suitable for operation at temperatures above 200.degree. C. and during temperature excursions between -65.degree. C. and at least 350.degree. C. The invention comprises a diode having respective p-n portions with a p-n junction therebetween, and formed of a semiconductor material that is stable and will exhibit satisfactory diode characteristics at such temperatures. Ohmic contacts are made to the opposite sides of the junction diode and to the respective p and n portions of the diode. An electrode adjacent each of the ohmic contacts is formed of an electrically conductive material that has a coefficient of thermal expansion similar to the coefficient of thermal expansion of the semiconductor material for providing structural support to the junction diode and electrical contact therewith. A lead contacts each of the electrodes opposite each electrode's contact with the diode.
    Type: Grant
    Filed: December 7, 1989
    Date of Patent: April 16, 1991
    Assignees: General Instrument Corporation, Cree Research, Inc.
    Inventors: John A. Edmond, Douglas G. Waltz, Muni M. Mitchell, Mohammad Sedigh, Roman Hamerski
  • Patent number: 4891685
    Abstract: A rectifier is fabricated from a P-N junction having a P-type semiconductor layer and an adjacent N-type semiconductor layer. A mesa structure is formed in at least one of said layers. Impurities are deposited at the top of the mesa to form a high concentration region in the surface thereof. The impurities are diffused from the top surface of the mesa toward the P-N junction, whereby the mesa geometry causes the diffusion to take on a generally concave shape as it penetrates into the mesa. The distance between the perimeter of the high concentration region and the wafer substrate is therefore greater than the distance between the central portion of said region and the wafer substrate, providing improved breakdown voltage characteristics and a lower surface field. Breakdown voltage can be measured during device fabrication and precisely controlled by additional diffusions to drive the high concentration region to the required depth.
    Type: Grant
    Filed: January 11, 1988
    Date of Patent: January 2, 1990
    Assignee: General Instrument Corporation
    Inventors: Willem G. Einthoven, Muni M. Mitchell
  • Patent number: 4740477
    Abstract: A rectifier is fabricated from a P-N junction having a P-type semiconductor layer and an adjacent N-type semiconductor layer. A mesa structure is formed in at least one of said layers. Impurities are deposited at the top of the mesa to form a high concentration region in the surface thereof. The impurities are diffused from the top surface of the mesa toward the P-N junction, whereby the mesa geometry causes the diffusion to take on a generally concave shape as it penetrates into the mesa. The distance between the perimeter of the high concentration region and the wafer substrate is therefore greater than the distance between the central portion of said region and the wafer substrate, providing improved breakdown voltage characteristics and a lower surface field. Breakdown voltage can be measured during device fabrication and precisely controlled by additional diffusions to drive the high concentration region to the required depth.
    Type: Grant
    Filed: October 4, 1985
    Date of Patent: April 26, 1988
    Assignee: General Instrument Corporation
    Inventors: Willem G. Einthoven, Muni M. Mitchell
  • Patent number: 4379305
    Abstract: A power, V-grooved MOSFET having V-grooves extending in two orthogonal dimensions, thereby forming a semi-continuous mesh grid configuration which maximizes the periphery of the MOSFET channels for a given area of silicon, thus providing higher output current and lower "on resistance" for a given area than a conventional, interdigitated V-MOS power transistor having V-grooves running in only one dimension.
    Type: Grant
    Filed: May 29, 1980
    Date of Patent: April 5, 1983
    Assignee: General Instrument Corp.
    Inventor: Muni M. Mitchell