Quality factor control of mechanical resonators using variable phononic bandgap on periodic microstructures

Naoki Inomata,Takahito Ono,Yuka Tonsho

doi:10.1038/s41598-021-04459-2

Naoki Inomata, Takahito Ono + Show 1 more

Open Access

https://doi.org/10.1038/s41598-021-04459-2

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Journal: Scientific Reports	Publication Date: Jan 10, 2022
Citations: 8	License type: open-access

Affiliation: Tohoku University

Abstract

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.

Highlights

The quality factor (Q-factor) is an important parameter for mechanical resonant sensors, and the optimal values depend on its application
The quality factor (Q-factor) and its control techniques are one of the key parameters for mechanical resonant sensors because the optimal values depend on its applications, i.e., high resolution and low response speed resulting from a higher Q-factor and vice versa
The vibration spectra of the mechanical resonators assembled at the center of the periodic microstructure were measured

Summary

Introduction

The quality factor (Q-factor) is an important parameter for mechanical resonant sensors, and the optimal values depend on its application. We demonstrate Q-factor control using a variable phononic bandgap by changing the length of the periodic microstructure. Electrical feedback m ethods[6,7,8,9,10], optical pumping[11,12,13,14,15,16,17,18,19], mechanical p umping[20,21,22,23,24], thermal pumping[25,26,27,28], and parametric pumping[29,30,31,32,33,34] are conventionally used for Q-factor control Nonlinear damping is another method that can be made effective by changing the vibration amplitude of the nanomechanical resonators[35]. The results did not describe a specific frequency range, the bandgap was changed by mechanically changing the structure

Methods

Results

Conclusion