A Piezoelectric MEMS Microphone Based on Lead Zirconate Titanate (PZT) Thin Films
Final rept. Dec 2002-Jul 2004
ARMY RESEARCH LAB ADELPHI MD SENSORS AND ELECTRON DEVICES DIRECTORATE
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Piezoelectric microelectromechanical MEMS scale acoustic sensors have potential applications in a wide variety of applications including hearing aids, surveillance, and heart monitoring. For each of these systems and many others, the acoustic sensors must be miniaturized and have low power requirements. A piezoelectric-based microphone can provide a solution to these requirements, since it offers the ability to passively sense without the power requirements of condenser or piezoresistive microphone counterparts. This research effort reports on the design and fabrication of a piezoelectric PbZr0.52Ti0.48O3PZT based acoustic sensor. A circular clamped membrane consisting of a dielectric for structural support and a piezoelectric actuator has been fabricated on a silicon wafer via silicon deep reactive ion etching DRIE. Sensors ranging from 500 to 2000 microns in diameter have been fabricated and characterized with the use of scanning laser Doppler vibrometry and calibrated acoustic tone source. The PZT sensors exhibited a sensitivity of 97.9 to 920 nVPa, depending on geometry.
- Electrical and Electronic Equipment