Investigation of high-quality-factor aluminum nitride MEMS cantilever resonators

Abstract

This paper presents the design, fabrication, and characterization of cantilever-type resonators with a novel stacked structure. Aluminum nitride is adopted as the material for both the structural layer and the piezoelectric layer; this simplifies the fabrication process and improves the quality factor of the resonator. Both in-plane and out-of-plane flexural modes were investigated. The effect of the structural dimensions and electrode patterns on the resonator’s performance were also studied. Finite-element simulations and experiments examining anchor loss and thermoelastic damping, which are the main loss mechanisms affecting the quality factor of these resonators, were carried out. The optimal structural dimensions and electrode patterns of the cantilever-type resonators are presented. A quality factor of 7922 with a motional impedance of 88.52 kΩ and a quality factor of 8851 with a motional impedance of 67.03 kΩ were achieved for the in-plane and out-of-plane flexural-mode resonators, respectively. The proposed resonator design will contribute to the development of high-performance devices such as accelerometers, gyroscopes, and pressure sensors.