Anchor Loss Reduction in Micro-Electro Mechanical Systems Flexural Beam Resonators Using Trench Hole Array Reflectors

Area of Science:

• Materials Science and Engineering
• Mechanical Engineering
• Electrical Engineering

Background:

• The quality factor (Q) is a critical parameter for microelectromechanical systems (MEMS) resonators, directly impacting their performance.
• Minimizing anchor loss is essential for enhancing the Q factor, driving research into novel resonator designs and fabrication techniques.

Purpose of the Study:

• To investigate the efficacy of elastic wave reflectors in improving the quality factor of MEMS clamped-clamped flexural beam resonators.
• To evaluate the impact of different reflector geometries, including square and half-circle shaped holes, on resonator Q factor.

Main Methods:

• Numerical simulations using a 2D in-plane wave propagation model with low-reflecting boundary conditions were employed to predict resonator behavior.
• Fabrication of MEMS resonator prototypes utilizing a standard micro-fabrication process.
• Experimental analysis of fabricated resonators to validate simulation results and quantify Q factor improvements.

Main Results:

• Half-circle shaped elastic wave reflectors, with curved sides oriented towards the anchors, demonstrated the most significant improvement in Q factor.
• Resonators equipped with optimized half-circle reflectors achieved a Q factor enhancement of 1.70× in air and 1.72× in vacuum.
• Comparison of different reflector shapes (squares and half-circles) revealed distinct effects on wave propagation and energy dissipation.

Conclusions:

• Elastic wave reflectors, particularly strategically placed half-circle holes, are an effective method for mitigating anchor loss in MEMS resonators.
• The study validates the use of numerical simulations and experimental fabrication for optimizing MEMS resonator performance.
• The findings offer a pathway to developing higher-performance MEMS resonators for various sensing and actuation applications.