Patents by Inventor William R. Heffner

William R. Heffner 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).

  • Publication number: 20040217475
    Abstract: A novel contact structure and method for a multilayer gettering contact metallization is provided utilizing a thin layer of a pure metal as the initial layer formed on a semiconductor cap layer. During formation of the contact structure, this thin metal layer reacts with the cap layer and the resulting reacted layer traps mobile impurities and self-interstitials diffusing within the cap layer and in nearby metal layers, preventing further migration into active areas of the semiconductor device. The contact metallization is formed of pure metal layers compatible with each other and with the underlying semiconductor cap layer such that depth of reaction is minimized and controllable by the thickness of the metal layers applied. Thin semiconductor cap layers, such as InGaAs cap layers less than 200 nm thick, may be used in the present invention with extremely thin pure metal layers of thickness 10 nm or less, thus enabling an increased level of integration for semiconductor optoelectronic devices.
    Type: Application
    Filed: May 27, 2004
    Publication date: November 4, 2004
    Inventors: Gustav E. Derkits, William R. Heffner, Padman Parayanthal, Patrick J. Carroll, Ranjani C. Muthiah
  • Publication number: 20030141599
    Abstract: A novel contact structure and method for a multilayer gettering contact metallization is provided utilizing a thin layer of a pure metal as the initial layer formed on a semiconductor cap layer. During formation of the contact structure, this thin metal layer reacts with the cap layer and the resulting reacted layer traps mobile impurities and self-interstitials diffusing within the cap layer and in nearby metal layers, preventing further migration into active areas of the semiconductor device. The contact metallization is formed of pure metal layers compatible with each other and with the underlying semiconductor cap layer such that depth of reaction is minimized and controllable by the thickness of the metal layers applied. Thin semiconductor cap layers, such as InGaAs cap layers less than 200 nm thick, may be used in the present invention with extremely thin pure metal layers of thickness 10 nm or less, thus enabling an increased level of integration for semiconductor optoelectronic devices.
    Type: Application
    Filed: February 4, 2003
    Publication date: July 31, 2003
    Inventors: Gustav E. Derkits, William R. Heffner, Padman Parayanthal, Patrick J. Carroll, Ranjani C. Muthiah
  • Patent number: 6555457
    Abstract: A novel contact structure and method for a multilayer gettering contact metallization is provided utilizing a thin layer of a pure metal as the initial layer formed on a semiconductor cap layer. During formation of the contact structure, this thin metal layer reacts with the cap layer and the resulting reacted layer traps mobile impurities and self-interstitials diffusing within the cap layer and in nearby metal layers, preventing further migration into active areas of the semiconductor device. The contact metallization is formed of pure metal layers compatible with each other and with the underlying semiconductor cap layer such that depth of reaction is minimized and controllable by the thickness of the metal layers applied. Thin semiconductor cap layers, such as InGaAs cap layers less than 200 nm thick, may be used in the present invention with extremely thin pure metal layers of thickness 10 nm or less, thus enabling an increased level of integration for semiconductor optoelectronic devices.
    Type: Grant
    Filed: April 7, 2000
    Date of Patent: April 29, 2003
    Assignee: Triquint Technology Holding Co.
    Inventors: Gustav E. Derkits, Jr., William R. Heffner, Padman Parayanthal, Patrick J. Carroll, Ranjani C. Muthiah
  • Patent number: 6255707
    Abstract: The invention relates to semiconductor lasers and more particularly to structures which enable the semiconductor lasers to be tested for reliability. The invention further relates to methods for testing the reliability of semiconductor lasers in wafer or chip form. The invention also relates to methods for the fabrication of semiconductor lasers which includes the use of reliability tests in the fabrication process where the reliability tests includes measuring the voltage drop or drops across one or more levels of a laser structure during the passage of current through the structure.
    Type: Grant
    Filed: August 24, 1998
    Date of Patent: July 3, 2001
    Assignee: Lucent Technologies, Inc.
    Inventors: Richard B. Bylsma, Gustav E. Derkits, Jr., William R. Heffner
  • Patent number: 4529271
    Abstract: A matrix addressed, bistable liquid crystal optical display is disclosed. The display includes a liquid crystal twist cell which has at least two states which are stable in the presence of a single given holding voltage. A form of 3:1 matrix addressing is used in the display which enhances operational characteristics.
    Type: Grant
    Filed: March 12, 1982
    Date of Patent: July 16, 1985
    Assignee: AT&T Bell Laboratories
    Inventors: Dwight W. Berreman, William R. Heffner, Allan R. Kmetz
  • Patent number: 4505548
    Abstract: A bistable liquid crystal twist cell is disclosed. The cell has at least two states which are stable in the presence of a single given holding voltage. The states may be switched from one to the other by short-term variation in the magnitude of the applied voltage.
    Type: Grant
    Filed: October 12, 1983
    Date of Patent: March 19, 1985
    Assignee: AT&T Bell Laboratories
    Inventors: Dwight W. Berreman, William R. Heffner
  • Patent number: 4239345
    Abstract: A bistable liquid crystal twist cell is disclosed. The cell is characterized by at least two stable states which exist indefinitely as long as not external energy is applied to the cell. External energy is necessary only for switching the cell between the stable states. Cell configurations which permit the fabrication of patterned displays are additionally disclosed. Specific embodiments include new techniques for switching the cell between the stable states.
    Type: Grant
    Filed: April 16, 1979
    Date of Patent: December 16, 1980
    Assignee: Bell Telephone Laboratories, Incorporated
    Inventors: Dwight W. Berreman, William R. Heffner