With Piezoelectric Microphone Patents (Class 381/114)
  • Integrated electroacoustic transducer with built-in bias
    Patent number: 4524247
    Abstract: Disclosed is an electroacoustic transducer structure which can be formed in a semiconductor substrate and incorporated as part of an integrated circuit, and which provides a built-in dc bias for operation. An appropriate density of fixed charge is provided in an insulating layer adjacent to one of the electrodes in the gap between electrodes. Methods of manufacture are also disclosed including means for introducing the charge by contacting the insulating layer with a liquid medium, plasma charging, or by ion beam implanting into the layer.
    Type: Grant
    Filed: July 7, 1983
    Date of Patent: June 18, 1985
    Assignee: AT&T Bell Laboratories
    Inventors: W. Stewart Lindenberger, Tommy L. Poteat, James E. West