薄膜体声波传感器的有限元仿真与分析

薄膜体声波滤波器(FBAR)传感器的性能受结构和材料特性的影响很大。该文利用COMSOL Multiphysics有限元仿真软件,建立了FBAR传感器的二维、三维有限元结构模型。用氮化铝和氧化锌材料作为压电薄膜对建立的模型做了固体力学和静电学仿真分析,得到了FBAR传感器的谐振频率、导纳特性曲线和谐振频率处的位移分布情况。通过分析发现氮化铝压电薄膜阻抗特性曲线更平滑,而氧化锌压电薄膜存在明显的寄生谐振峰的问题。针对氧化锌压电薄膜存在的寄生谐振峰进行了优化,仿真分析了电极边长尺寸和电极厚度对寄生谐振的影响,实现了对寄生谐振峰的有效抑制。

Finite Element Simulation and Analysis of Thin Film Bulk Acoustic Sensor

The performance of the thin film bulk acoustic (FBAR) sensor is greatly influenced by the structure and material properties. In this paper, the finite element simulation software of COMSOL Multiphysics is used to establish the 2D and 3D finite element model of FBAR sensor. The solid mechanics and electrostatics simulation analysis are carried out by using the aluminum nitride and Zinc Oxide piezoelectric thin film materials as the model, and the displacement distribution of the resonant frequency, the admittance curve and the resonant frequency of FBAR sensor. Through the analysis, it is found that the impedance characteristic curve of AlN thin film is smoother and the resonant frequency is higher, but there is a problem of parasitic resonance peak in the Zinc Oxide piezoelectric film. The parasitic resonance peak in the piezoelectric film of Zinc Oxide is optimized, the influence of electrode size and electrode thickness on parasitic resonance is analyzed, and the effective suppression of parasitic resonance peak is achieved. It provides a reliable theoretical basis for the application of thin film bulk acoustic sensor.