Integrated electroacoustic transducer with built-in bias

摘要

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.