Design, Fabrication, and Characterization of a Piezoelectric AFM Cantilever Array

Atomic force microscope (AFM) is a powerful instrument, which has been successfully employed in a myriad of applications from imaging to lithography, over the last decades. Despite its widespread use, low throughput of the AFM remains one of its major limitations along with slow scan rates in tapping mode. In this work, we propose a microfabricated cantilever array composed of five cantilevers, each equipped with on-chip piezoelectric displacement sensors and an actuator for parallel imaging in tapping mode. The cantilevers are designed to have separate resonance frequencies in order to effectively minimize the vibrational coupling. The measured resonance frequencies range from 85.34 kHz to 107.78 kHz, and more than 5 kHz resonant frequency separation is achieved in the neighboring cantilevers. Vibrational coupling is mitigated by over two orders of magnitude compared to arrays with identical cantilevers. The common feedthrough problem in this type of active system is addressed by configuring the displacement sensors differentially. Finally, one of the cantilevers in the array is successfully employed for tapping mode AFM imaging.