Effective quality factor tuning mechanisms in micromechanical resonators

• Published in: Applied Physics Reviews Vol. 5; no. 4
• Main Authors: Miller, James M. Lehto, Ansari, Azadeh, Heinz, David B., Chen, Yunhan, Flader, Ian B., Shin, Dongsuk D., Villanueva, L. Guillermo, Kenny, Thomas W.
• Format: Book Review
• Language: English
• Published: 01.12.2018
• ISSN: 1931-9401
• DOI: 10.1063/1.5027850

Quality factor (Q) is an important property of micro- and nano-electromechanical (MEM/NEM) resonators that underlie timing references, frequency sources, atomic force microscopes, gyroscopes, and mass sensors. Various methods have been utilized to tune the effective quality factor of MEM/NEM resonators, including external proportional feedback control, optical pumping, mechanical pumping, thermal-piezoresistive pumping, and parametric pumping. This work reviews these mechanisms and compares the effective Q tuning using a position-proportional and a velocity-proportional force expression. We further clarify the relationship between the mechanical Q, the effective Q, and the thermomechanical noise of a resonator. We finally show that parametric pumping and thermal-piezoresistive pumping enhance the effective Q of a micromechanical resonator by experimentally studying the thermomechanical noise spectrum of a device subjected to both techniques.