Ultrasonic transducers are generally based on the piezoelectric effect and they are used in a variety of applications (medical imaging, NDE, ranging). Some of the main reasons for choosing an alternative technology, based on electrostatic effect, are low impedance mismatch with air and in water, low energy density, high efficiency, low costs, good integration with control electronics. Capacitive ultrasonic transducer consists in a parallel plates capacitor (like a condensor microphone) with a fixed electrode and a free one (membrane). A cMUT (capacitive Micromachined Ultrasonic Transducer) consists of an array of capacitive ultrasonic transducer with a metallized membranes suspended on silicon bulk. The membrane thickness is 0.4 micrometers . Tests of these transducers ( 2.5 MHz) fabricated in our laboratories are in progress.

Date Published: 15 August 2000
PDF: 9 pages
Proc. SPIE 4176, Micromachined Devices and Components VI, (15 August 2000); doi: 10.1117/12.395636

Published in SPIE Proceedings Vol. 4176:
Micromachined Devices and Components VI
Eric Peeters; Oliver Paul, Editor(s)