Design of a Multiple Folded-Beam Disk Resonator with High Quality Factor

Area of Science:

• Materials Science
• Mechanical Engineering
• Physics

Background:

• Thermoelastic damping (TED) is a major limiting factor for the quality factor (Q) in microelectromechanical systems (MEMS) resonators.
• Disk resonators are widely used in MEMS due to their compact size and high frequency operation.
• Improving the Q factor is crucial for enhancing the performance and sensitivity of MEMS devices.

Purpose of the Study:

• To design and fabricate a novel multiple folded-beam disk resonator with enhanced thermoelastic quality factor.
• To investigate the impact of beam width reduction and lumped masses on resonator performance.
• To explore the potential of the new resonator design for MEMS gyroscope applications.

Main Methods:

• Finite element analysis was used to optimize the resonator geometry.
• Fabrication of the disk resonator using (100) single crystal silicon.
• Experimental characterization of the resonator's quality factor and frequency response.
• Temperature-dependent experiments to identify damping mechanisms.

Main Results:

• Achieved a record-high quality factor of 710,000 in the fabricated silicon disk resonator.
• Demonstrated significant improvement in thermoelastic quality factor through beam width reduction and lumped mass integration.
• Observed a small initial frequency split in the order-3 working modes, suitable for gyroscope applications.
• Experimental results indicated that thermoelastic damping is no longer the dominant damping mechanism.

Conclusions:

• The novel multiple folded-beam disk resonator design significantly enhances the quality factor, surpassing previous records for silicon disk resonators.
• The resonator's design modifications effectively mitigate thermoelastic damping, opening new avenues for high-performance MEMS.
• The achieved performance and mode characteristics make this resonator a promising candidate for advanced MEMS gyroscope applications.