Reduction of Motional Resistance Using Piezoelectric on Silicon MEMS Disk Arrays for Ambient Air Applications

• Published in: Journal of microelectromechanical systems Vol. 34; no. 4; pp. 459 - 471
• Main Authors: Ali, Abid, Tariq Balghari, Suaid, Wajih Ullah Siddiqi, Muhammad, Nabki, Frederic
• Format: Journal Article
• Language: English
• Published: New York IEEE 01.08.2025; The Institute of Electrical and Electronics Engineers, Inc. (IEEE)
• Subjects: Arrays; Bulk mode; Contours; Coupling coefficients; Couplings; differential drive; differential sense; Electrodes; Fabrication; mechanical coupling; Microelectromechanical systems; Micromechanical devices; Motional resistance; Phase noise; piezoelectric array; Piezoelectricity; Q factors; Q-factor; quality factor; Resistance; Resonance; Resonant frequency; Resonators; Strain; timing application
• ISSN: 1057-7157; 1941-0158
• DOI: 10.1109/JMEMS.2025.3571721

This paper presents the implementation of a piezoelectric contour resonance mode in a micro-electro-mechanical (MEM) disk resonator array, fabricated using a low-cost, commercially available MEMS technology. The resonator operates in a Button-like (BL) mode, which is suitable for a fully differential piezoelectric transduction mechanism. Compared to other modes, such as the anti-symmetric (AS) mode and the Higher wine glass (HWG) mode, the BL mode offers a higher quality factor ( Q ) and a reasonable coupling coefficient (<inline-formula> <tex-math notation="LaTeX">k_{t}^{2} </tex-math></inline-formula>) for the same perimeter around the disk device. The mechanical coupling and excitation of a parallel array of nodal point-coupled piezoelectric disk resonators significantly reduce the motional resistance ( R m ) of the vibrating disk MEMS resonator, making the BL mode highly attractive due to the achieved performance improvements. The implementation of this method with three resonators results in an effective motional resistance of <inline-formula> <tex-math notation="LaTeX">101~\Omega </tex-math></inline-formula> at 32 MHz under ambient air conditions. This value is approximately 3.9 times lower ( Q ul normalized) than the R m of <inline-formula> <tex-math notation="LaTeX">822~\Omega </tex-math></inline-formula> exhibited by a single contour mode disk resonator. Additionally, an unloaded quality factor ( Q ul ) of 8,230 is observed when operating at 0 dBm power in ambient air. Notably, these enhancements are achieved while maintaining an effective <inline-formula> <tex-math notation="LaTeX">Q_{ul} \gt 10,000 </tex-math></inline-formula>, as measured in vacuum conditions, along with notable power-handling capabilities in both ambient air and vacuum environments. This work also investigates two other contour resonance modes with the same design considerations to further validate the proposed methodology. [2025-0006]