| This paper describes piezoelectric MEMS that offer competitive advantages over existing commercial technologies in audio, ultrasonic, air borne, microfluidic and RF applications. Specifically, a piezoelectric microphone requires a much simpler fabrication process than a condenser microphone, while a piezoelectric microspeaker is both planar and amenable to MEMS process for mass production unlike an electrodynamic speaker. Micromachined self-focusing acoustic transducers can eject picoliter liquid droplet in any oblique angle, without any clog-prone nozzle. Resonant mass sensors based on film bulk-acoustic resonators (FBAR) offer inherently higher sensitivity and smaller active area than a quartz microbalance. Piezoelectrically actuated cantilever can be moved in both directions (i.e., into and away-from a stationary electrode) unlike an electrostatically actuated cantilever, and provides a wide tuning ratio for a tunable capacitor. |