In this Letter, an active area optimisation technique to improve the performance parameters of the film bulk acoustic resonator (FBAR) is proposed. The active area of the back trench membrane-based FBAR is optimised to remove the spurious modes, higher harmonic modes, and to confine the acoustic signal at its central part during the resonance. The effect of thickness variation of SiO2 layer on the performance parameters was studied using finite-element analysis (FEA) simulation. The SiO2 film, on silicon substrate, was used as the support layer and zinc oxide was used as the piezoelectric film for the resonator. The authors have successfully demonstrated the FBAR through FEA for an optimised active area of 320 × 320 µm2, series resonance frequency (f s) 1.249 GHz, and parallel resonance frequency (f p) 1.273 GHz with an effective electromechanical coupling coefficient ( k eff 2 ) of 4.65%.

中文翻译：

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薄膜体声波谐振器有源区优化改进性能参数

在这封信中，提出了一种用于改善薄膜体声波谐振器 (FBAR) 性能参数的有源区域优化技术。基于后沟膜的 FBAR 的有源区经过优化，以去除杂散模式、高次谐波模式，并在共振期间将声学信号限制在其中心部分。使用有限元分析 (FEA) 模拟研究了 SiO2 层厚度变化对性能参数的影响。硅衬底上的 SiO2 膜用作支撑层，氧化锌用作谐振器的压电膜。作者已通过 FEA 成功演示了 FBAR，优化的有源面积为 320 × 320 µm2，串联谐振频率 (fs) 为 1.249 GHz，并联谐振频率 (fp) 为 1。