Demonstration of 1 Million Q -Factor on Microglassblown Wineglass Resonators With Out-of-Plane Electrostatic Transduction

• Published in: Journal of microelectromechanical systems 2015-02, Vol.24 (1), p.29-37
• Main Authors: Senkal, Doruk, Ahamed, Mohammed J., Ardakani, Mohammad H. Asadian, Askari, Sina, Shkel, Andrei M.
• Format: Article
• Language: English
• Subjects: 3-D MEMS; Cavity resonators; degenerate mode gyroscope; Electrodes; Finite element analysis; fused silica; Glass; Micro-glassblowing; Q-factor; Silicon compounds; wineglass resonator
• ISSN: 1057-7157; 1941-0158
• DOI: 10.1109/JMEMS.2014.2365113

In this paper, we report Q-factor over 1 million on both n = 2 wineglass modes, and high-frequency symmetry (Af/f ) of 132 ppm on wafer-level microglassblown 3-D fused silica wineglass resonators at a compact size of 7-mm diameter and center frequency of 105 kHz. In addition, we demonstrate for the first time, out-of-plane capacitive transduction on microelectromechanical systems wineglass resonators. High Q-factor is enabled by a high aspect ratio, self-aligned glassblown stem structure, careful surface treatment of the perimeter area, and low internal loss fused silica material. Electrostatic transduction is enabled by detecting the spatial deformation of the 3-D wineglass structure using a new out-of-plane electrode architecture. Out-of-plane electrode architecture enables the use of sacrificial layers to define the capacitive gaps and 10 μm capacitive gaps have been demonstrated on a 7-mm shell, resulting in over 9 pF of active capacitance within the device. Microglassblowing may enable batch-fabrication of high-performance fused silica wineglass gyroscopes at a significantly lower cost than their precision-machined macroscale counterparts.