Approaches to the design, fabrication, and test of electroacoustic micro-transducers

Silicon-based microphones are nowadays well-established MEMS components produced by strong industrial actors. The fabrication of such acoustic sensors is based on a dedicated technology fulfilling all designed parameters. On the other hand, the development of such a technology processes is costly and time-consuming. In this paper, we will present approaches based on technologies readily available to small companies and academic institutions. We will show, on several examples, a design process of acoustic micro-transducers fabricated through generic technologies. Focused will be a CMOS-MEMS process applied to the realization of suspended diaphragms that can be part of transducers with piezoresistive, electrostatic, or electrodynamic transduction. We will also briefly present a testing technique that can be used for acoustic sensors calibration. This technique has a special interest for sensors with a frequency response exceeding the typical audible range.