Inomata Naoki, Tonsho Yuka, Ono Takahito
Graduate School of Engineering, Tohoku University, Sendai, 980-8579, Japan.
Sci Rep. 2022 Jan 10;12(1):392. doi: 10.1038/s41598-021-04459-2.
The quality factor (Q-factor) is an important parameter for mechanical resonant sensors, and the optimal values depend on its application. Therefore, Q-factor control is essential for microelectromechanical systems (MEMS). Conventional methods have some restrictions, such as additional and complicated equipment or nanoscale dimensions; thus, structural methods are one of the reasonable solutions for simplifying the system. In this study, we demonstrate Q-factor control using a variable phononic bandgap by changing the length of the periodic microstructure. For this, silicon microstructure is used because it has both periodicity and a spring structure. The bandgap change is experimentally confirmed by measuring the Q-factors of mechanical resonators with different resonant frequencies. The bandgap range varies depending on the extended structure length, followed by a change in the Q-factor value. In addition, the effects of the periodic structure on the Q-factor enhancement and the influence of stress on the structural length were evaluated. Although microstructures can improve the Q-factors irrespective of periodicity; the result of the periodic microstructure is found to be efficient. The proposed method is feasible as the novel Q-factor control technique has good compatibility with conventional MEMS.
品质因数（Q 因子）是机械谐振传感器的一个重要参数，其最佳值取决于应用。因此，Q 因子控制对于微机电系统（MEMS）至关重要。传统方法存在一些限制，例如需要额外且复杂的设备或纳米级尺寸；因此，结构方法是简化系统的合理解决方案之一。在本研究中，我们通过改变周期性微结构的长度，利用可变声子带隙来演示 Q 因子控制。为此，使用硅微结构，因为它既具有周期性又具有弹簧结构。通过测量具有不同谐振频率的机械谐振器的 Q 因子，实验证实了带隙变化。带隙范围随扩展结构长度而变化，随后 Q 因子值也发生变化。此外，评估了周期性结构对 Q 因子增强的影响以及应力对结构长度的影响。尽管微结构无论周期性如何都能提高 Q 因子，但发现周期性微结构的效果更显著。所提出的方法是可行的，因为这种新型 Q 因子控制技术与传统 MEMS 具有良好的兼容性。
