Liu Jieyu, Liu Wenjuan, Wen Zhiwei, Zeng Min, Cai Yao, Sun Chengliang
The Institute of Technological Sciences, Wuhan University, Wuhan 430072, China.
Hubei Key Laboratory of Electronic Manufacturing and Packaging Integration, Wuhan University, Wuhan 430072, China.
Sensors (Basel). 2025 Mar 11;25(6):1740. doi: 10.3390/s25061740.
With the development of piezoelectric-on-insulator (POI) substrates, X-cut LiNbO thin-film resonators with interdigital transducers are widely investigated due to their adjustable resonant frequency () and effective electromechanical coupling coefficient (Keff2). This paper presents an in-depth study of simulations and measurements of laterally excited bulk acoustic wave resonators based on an X-cut LiNbO/SiO/Si substrate and a LiNbO thin film to analyze the effects of electrode angle rotation (θ) on the modes, , and Keff2. The rotated θ leads to different electric field directions, causing mode changes, where the resonators without cavities are longitudinal leaky SAWs (LLSAWs, θ = 0°) and zero-order shear horizontal SAWs (SH-SAWs, θ = 90°) and the resonators with cavities are zero-order-symmetry (S) lateral vibrating resonators (LVRs, θ = 0°) and SH plate wave resonators (PAW, θ = 90°). The resonators are fabricated based on a 400 nm X-cut LiNbO thin-film substrate, and the measured results are consistent with those from the simulation. The fabricated LLSAW and SH-SAW without cavities show a Keff2 of 1.62% and 26.6% and a Bode- of 1309 and 228, respectively. Meanwhile, an S LVR and an SH-PAW with cavities present a Keff2 of 4.82% and 27.66% and a Bode- of 3289 and 289, respectively. In addition, the TCF with a different rotated θ is also measured and analyzed. This paper systematically analyzes resonators on X-cut LiNbO thin-film substrates and provides potential strategies for multi-band and multi-bandwidth filters.
随着绝缘体上压电（POI）衬底的发展，具有叉指换能器的X切LiNbO薄膜谐振器因其可调谐谐振频率（）和有效机电耦合系数（Keff2）而受到广泛研究。本文对基于X切LiNbO/SiO/Si衬底和LiNbO薄膜的横向激发体声波谐振器进行了深入的模拟和测量研究，以分析电极角度旋转（θ）对模式、和Keff2的影响。旋转的θ导致不同的电场方向，从而引起模式变化，其中无腔谐振器为纵向泄漏表面声波（LLSAW，θ = 0°）和零阶水平剪切表面声波（SH-SAW，θ = 90°），有腔谐振器为零阶对称（S）横向振动谐振器（LVR，θ = 0°）和SH板波谐振器（PAW, θ = 90°）。谐振器基于400 nm的X切LiNbO薄膜衬底制造，测量结果与模拟结果一致。制造的无腔LLSAW和SH-SAW的Keff2分别为1.62%和26.6%，品质因数分别为1309和228。同时，有腔的S LVR和SH-PAW的Keff2分别为4.82%和27.66%，品质因数分别为3289和289。此外，还测量和分析了不同旋转θ下的温度系数（TCF）。本文系统地分析了X切LiNbO薄膜衬底上的谐振器，并为多频段和多带宽滤波器提供了潜在策略。
