Traveling wave annular ultrasonic micromotors using bulk PZT

This paper describes the development a novel traveling wave ultrasonic micromotor fabricated directly from low-cost and high-performance bulk piezoceramic PZT. We report a simpler approach to realizing traveling wave ultrasonic micromotors in which traveling waves are generated within a tethered annular stator microfabricated from a single sheet of bulk PZT. Actuation is achieved using interdigitated electrodes deposited on a single layer, enabling monolithic stators to be fabricated in a batch process from a single sheet of high quality bulk piezoceramic. The process requires only 2 photolithography steps, greatly simplifying design and manufacture while improving device performance and microfabrication costs.