AlN Checker-mode Resonators with Routing Structures

The paper presents a two-dimensional piezoelectric aluminum nitride (AlN) Lamb wave resonator (LWR) with a routing structure which can improve the electromechanical coupling coefficient $\left({K_{eff}^2}\right)$ and reduce spurious modes. In this work, electrodes are arranged on both sides of the piezoelectric layer with routing structure electrical lines which are distributed as a bridge to connect adjacent checkers and this design can successfully enhance acoustic performance. Different shape and thickness design of checker-mode resonators (CMR) are compared in this paper and results show that resonators with circle shaped electrodes have better performance comparable to resonators with hexagon and octagon ones. The simulated resonator with circle shaped electrodes presented in this work resonates at 2.71GHz and achieves high $K_{eff}^2$ of 5.12% as well as suppressing the spurious modes. Silicon dioxide (SiO2) between the piezoelectric layer and the routing structure can be used for temperature compensation. This work will play a referential role in the selection of resonator parameters in the future and lay the foundation in the field of high frequency and multi-band RF filters.