This paper aims to propose a new model to study the relationship between the acoustic properties of the thickness shear mode (TSM) in lateral field excited (LFE) film bulk acoustic wave resonator (FBAR) and the gap distance of the surface electrodes.
In the finite element analysis, harmonic and modal analyses are performed to obtain the admittance spectrum and determine the mechanical vibration mode. The results are used to modify the ideal model used in the theoretical calculation.
In the case of LFE FBAR, the acoustic velocity and electromechanical coupling coefficient (K2) of the TSM decreases as the gap distance decreases and there is a compromise between the exciting effectiveness and the acoustic properties.
The paper proposes a new method to study the dependences of the acoustic properties of the lateral field excited FBAR on the gap distances of the surface electrodes through the extraction of the static capacitance based on the finite element simulation results.
