DocumentCode :
5440
Title :
Reduced Residual Stress Curvature and Branched Comb Fingers Increase Sensitivity of MEMS Acoustic Sensor
Author :
Downey, Richard H. ; Karunasiri, G.
Author_Institution :
Dept. of Phys., Naval Postgrad. Sch., Monterey, CA, USA
Volume :
23
Issue :
2
fYear :
2014
fDate :
Apr-14
Firstpage :
417
Lastpage :
423
Abstract :
We present an enhanced in-plane capacitive readout for sensing out-of-plane displacement in a MEMS acoustic sensor. The sensor is fabricated in a multi-user silicon-on-insulator process, using a thicker device layer to reduce misalignment between moving and fixed comb fingers. This misalignment is found to reduce the sensitivity and render the response nonlinear. In addition, incorporation of a branched comb design doubles the readout capacitor surface area for a given sensor size, to further increase the sensitivity. These two modifications restore linearity to the readout and increase its sensitivity to displacement by an order of magnitude.
Keywords :
acoustic devices; capacitive sensors; internal stresses; microfabrication; microsensors; readout electronics; silicon-on-insulator; thin film sensors; MEMS acoustic sensor fabrication; Si; branched comb finger design; in-plane capacitive readout; linearity restoration; misalignment reduction; multiuser silicon-on-insulator process; nonlinear response; reduced residual stress curvature; sensing out-of-plane displacement; thick device layer; Acoustic measurements; Capacitance; Capacitors; Resonant frequency; Sensitivity; Vibrations; Voltage measurement; Acoustic; MEMS; capacitive readout; sound sensor;
fLanguage :
English
Journal_Title :
Microelectromechanical Systems, Journal of
Publisher :
ieee
ISSN :
1057-7157
Type :
jour
DOI :
10.1109/JMEMS.2013.2279017
Filename :
6595588
Link To Document :
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