空腔型压电薄膜体声波谐振器的仿真研究

Simulation Research on Cavity Piezoelectric Film Bulk Acoustic Resonator

微机电加工技术的迅速发展与集成电路技术的日益成熟,射频前端设备中的器件朝着小型化、集成化方向发展。压电薄膜体声波谐振器(Film bulk acoustic resonator, FBAR)逐渐成为通信滤波器的研究热点之一。首先基于射频仿真软件ADS 2019,首先采用一维Mason等效电路模型对FBAR器件的谐振频率特性进行模拟,得到FBAR的各膜层厚度以及谐振面积均对频率-阻抗特性有影响。其次以此Mason模型的仿真结果确定各膜层的材料与厚度,根据压电层的材料厚度对MBVD模型的参数提取过程进行了说明。最后以MBVD为模型设计的FBAR的频率达到了3.4GHz及以上,串联谐振频率fs为3.714GHz,并联谐振频率fp为3.811GHz,且S21的值优于-3dB,具体为-0.156dB,有效机电耦合系数约为6.28%,串联谐振因子Qs约为621.17,并联谐振因子Qp约为666.54。

With the rapid development of micro-electromechanical processing technology and the increasing matu-rity of integrated circuit technology,the devices in the radio frequency front-end equipment are developing in the di-rection of miniaturization and integration.The piezoelectric film bulk acoustic resonator(FBAR)has gradually become one of the research hotspots of communication filters.In this paper,we first derived the FBAR's electrical impedance theoretical model,and then used the 1-D Mason model to simulate the resonant frequency characteristics of the FBAR device based on the radio frequency simulation software ADS 2019,and the film thickness and resonant area obtained form the FBAR have an influence on the frequency-impedance characteristics.Secondly,the material and thickness of each film layer were determined based on the simulation results of the Mason model,and the parameter extraction process of the MBVD model was explained according to the material thickness of the piezoelectric layer.Fi-nally,the frequency of the FBAR designed with MBVD as the model reached 3.4GHz and above,the series reso-nance frequency fs was 3.714GHz,the parallel resonance frequencyfp was 3.811GHz,and the value of S21 was bet-ter than-3dB,specifically-0.156dB,and the effective electromechanical coupling coefficient was about 6.28%,the series resonance factor Qs is about 621.17,and the parallel resonance factor Qp was about 666.54.