一种新型FBAR结构的设计

Design of a novel FBAR structure

针对传统FBAR(Film Buck Acoustic Resonator)制备困难、成品率低的问题,提出一种新型FBAR结构(SU8-FBAR)。利用高分子聚合物材料SU8薄膜代替传统FBAR的支撑层和声波限制结构,增加了FBAR器件的机械强度,且易于制备,成品率较高。采用AlN作压电薄膜,分别以Mo、Pt、CNT、Al作为电极,利用Comsol Multiphysics仿真软件对SU8-FBAR的结构参数进行仿真优化。结果显示,当电极材料为CNT、上电极厚度为0.1μm、SU8薄膜厚度为5μm时,SU8-FBAR的综合性能最优:SU8-FBAR的品质因数(Q)值达到1210,几乎为传统FBAR Q值的3倍;机电耦合系数为0.063,高于传统FBAR的0.0425。该器件能检测到极小谐振频率的变化,可用于微生物传感领域。

Aiming at the problem of difficult preparation and low yield of traditional film buck acoustic resonator ( FBAR), a novel FBAR structure ( SU8-FBAR) was proposed. A high-molecular polymer material SU8 was employed to instead of the support layer and the acoustic confinement structure of traditional FBAR, thus the mechanical strength was increased, so that it was easy to prepare and had a high yield. In SU8-FBAR, AlN was employed as the piezoelectric thin film, and Mo, Pt, CNT and Al were used as electrode materials. The structural parameters of SU8-FBAR were optimized using Comsol Multiphysics. The results show that when the electrode material is CNT, the thickness of upper electrode is 0. 1 μm, and the thickness of SU8 film is 5μm, the comprehensive performance of SU8-FBAR is optimal: the quality factor ( Q) value of SU8-FBAR reaches 1210, almost three times of the traditional FBAR Q value. The electromechanical coupling coefficient is 0. 063, higher than the 0. 0425 of traditional FBAR. The device can detect the change of the minimum resonant frequency and can be used in the field of microbiological sensing.