Piezoelectric MEMS wideband acoustic sensor coated by organic film

In this study, we developed an acoustic sensor with a structure in which a piezoelectric cantilever array is covered with an organic film. For this, we used AlN and polyurethane as the piezoelectric material and organic film, respectively. The results suggested that the sensitivity in the low-frequency region improved, and the resonance frequency increased. We investigated the resonance frequency based on a simulation and verified that it matched the measured value. Further, we created a broadband acoustic sensor by covering the space between the cantilevers with an organic film.