AlN Contour-Mode Resonators for Narrow-Band Filters above 3 GHz

Matteo Rinaldi, University of Pennsylvania
Chiara Zuniga, University of Pennsylvania
Chengjie Zuo, University of Pennsylvania
Gianluca Piazza, University of Pennsylvania

Abstract

This paper reports on the design and experimental verification of a new class of thin-film (250 nm) Super High Frequency (SHF) laterally-vibrating piezoelectric microelectromechanical (MEMS) resonators suitable for the fabrication of narrow-band MEMS filters operating at frequencies above 3 GHz. The device dimensions have been opportunely scaled both in the lateral and vertical dimensions in order to excite a contour-extensional mode of vibration in nano features of an ultra-thin (250 nm) Aluminum Nitride (AlN) film. In this first demonstration two-port resonators vibrating up to 4.5 GHz were fabricated on the same die and attained electromechanical coupling, kt2, in excess of 1.5 %. These devices were employed to synthesize the highest frequency ever reported MEMS filter (3.7 GHz) based on AlN contour-mode resonator (CMR) technology.