Air Damping Effects on Different Modes of AlN-on-Si Microelectromechanical Resonators
Air Damping Effects on Different Modes of AlN-on-Si Microelectromechanical Resonators
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DOI：
10.1109/mems49605.2023.10052273
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发表时间：
2023-01
期刊：
影响因子：
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通讯作者：
Yuncong Liu;S. M. Enamul Hoque Yousuf;Afzaal Qamar;M. Rais-Zadeh;P. Feng
中科院分区：
文献类型：
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作者：
Yuncong Liu;S. M. Enamul Hoque Yousuf;Afzaal Qamar;M. Rais-Zadeh;P. Feng
压电薄膜已经在当今的微机电系统（MEMS）工业中展示了广泛的硅上压电（PoS）谐振换能器。虽然真空封装中的实际环境压力(p)水平会极大地影响器件性能，但对多模PoS谐振器在变压力下的动态特性的全面研究和定量理解仍然缺乏，需要进一步研究。在这项工作中，我们报告了空气阻尼对硅铝（AlN/Si）体声谐振器（bar）体共振模式和弯曲共振模式的首次测量和分析。给出了共振频率f和质量Q因子的实验结果，p值从760Torr到100μTorr不等。对于AlN/Si谐振器的体模，f在压力范围内几乎保持恒定值10.291MHz，当p大于10Torr时，Q因子开始下降。对于AlN/Si谐振器的弯曲模态，f在20Torr以下稳定在595.3kHz，在760Torr时下降到595kHz。对于Si-only器件的批量模式，f ~10.127MHz与p无关，当p < 3Torr时保持高Q ~257,000。本研究清楚地揭示了空气阻尼对AlN/Si MEMS谐振器的体模和弯曲模的不同影响，为器件工程提供了新的定量知识和见解。
Piezoelectric thin films have enabled demonstrations of a wide range of piezoelectric-on-silicon (PoS) resonant transducers in microelectromechanical systems (MEMS) industry today. While the actual ambient pressure (p) levels in vacuum packages can greatly affect device performance, a comprehensive study and quantitative understanding of dynamical characteristics of multimode PoS resonators under varying pressure is still lacking and needs to be investigated. In this work, we report the first measurements and analyses of air damping effects on both bulk and flexural resonance modes of AlN-on-Si (AlN/Si) bulk acoustic resonators (BARs). Experimental results are presented for the resonant frequency (f) and quality (Q) factor with p varying from 760Torr down to 100μTorr. For AlN/Si resonator’s bulk mode, f keeps a nearly constant value of 10.291MHz over the pressure range and the Q factor starts to decline when p is above 10Torr. For AlN/Si resonator’s flexural mode, f is stable at 595.3kHz below 20Torr and drops to 595kHz at 760Torr. For the Si-only device’s bulk mode, f ~10.127MHz is independent of p, and a high Q ~257,000 is maintained when p < 3Torr. The present work clearly reveals the different effects that air damping exerts upon the bulk and flexural modes of AlN/Si MEMS resonators, providing new quantitative knowledge and insight for device engineering.