Piezoelectric cantilever microphone for photoacoustic GAS detector

New micromachined pressure sensors based on PZT coated silicon cantilevers have been fabricated and integrated in a photoacoustic gas detector. PZT Sol-gel thin films texture and composition were optimized with respect to the transverse piezoelectric coefficient e(31,f). A best value of -12 C/m(2) was obtained with (100)/(001) textured thin films at the MPB composition. Optimum stress compensation between the different layers composing the cantilever has been studied in order to yield flat cantilevers. A high response of 150 mV/Pa with a S/N of 700 at 1 Pa and 1 Hz bandwidth has been measured. The influence of the damping chamber under the cantilever is also reported.