Piezoelectric ALN cantilever array on a SU-8 substrate for flexible artificial basilar membrane

Artificial basilar membrane (ABM) has been developed to mimic the cochlea's transduction and mechanical frequency selectivity. In our previous study, ABM was designed as a cantilever array on silicon substrate using aluminum nitride. However, its frequency range was relatively high (2.92-12.6 kHz) compared to the communication range of human (300-3,400 Hz). To lower the frequency response range of the ABM, we fabricated piezoelectric aluminum nitride (AlN) cantilever array on a flexible SU-8 substrate. The deposited AlN thin film exhibited c-axis orientation on the cured SU-8 film, which was identified by SEM and XRD. The fabricated AlN cantilever array demonstrated piezoelectric characteristics with mechanical frequency selectivity, which is a vital function for artificial basilar membrane.