High- Q piezoelectric AlN MEMS cantilever resonator employing a comb-shaped electrode

Abstract Conventional fully covered electrodes in piezoelectric microelectromechanical (MEMS) cantilever resonators lead to uneven electric field distribution and the excitation of parasitic modes. Herein, the top and bottom electrodes are made of molybdenum and symmetrically configured in a comb-shaped layout. The proposed design significantly reduces metal coverage and mass loading, effectively suppresses parasitic modes, and demonstrates high drive efficiency. Finite element method simulations were conducted to optimize the device’s design, followed by the fabrication of the cantilever resonator on a silicon-on-insulator substrate, with aluminum nitride (AlN) selected as the piezoelectric material. Experimental measurements in vacuum reveal that the resonator exhibits a resonant frequency of 5.19 MHz and a quality factor of 6259, which is approximately 3.7 times higher than that of the conventional resonator. These results validate the effectiveness of the proposed electrode optimization strategy and offer valuable insights for the advancement of piezoelectric MEMS resonator technology.