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Electroacoustic and ultrasonic microtransducers

Auteur(s) : L. Rufer, C. Domingues, M. Wong, J. Dong, S. Mir

Doc. Source: 8th French Acoustical Congress

Pages : 487-490

This paper presents different transduction principles used in the development of micromachined electroacoustic and ultrasonic transducers. These principles are demonstrated through two different devices designed for a silicon compatible technology with post-CMOS MEMS device process. One of them, designed for the narrow frequency band centered at 40 kHz, is based on electro-thermal conversion for the membrane actuation and on the piezoresistive effect for the membrane movement detection. The other device is a microphone based on the electrostatic conversion covering the audible frequency range. We have chosen a low stress cantilever as the microphone movable electrode. Such a solution avoids the residual stress that is often present in typical membranes clamped on edges and allows high microphone sensitivity.