A multi-functional MEMS resonator for simultaneously dual-mode physical sensing and ppb-level timing

Area of Science:

• Microelectromechanical Systems (MEMS)
• Resonator Technology
• Nonlinear Dynamics

Background:

• Multifunctional MEMS resonators are limited by the integration of sensing and frequency referencing.
• This hinders advanced microsystems for precision applications.
• Existing designs face challenges in achieving compact, high-performance devices.

Purpose of the Study:

• To develop a novel MEMS resonator for the blue-sideband excitation (BSE) scheme.
• To enable simultaneous multi-mode actuation and study nonlinear mode coupling.
• To address limitations in integrating high-sensitivity sensing and high-stability frequency referencing.

Main Methods:

• Designed a MEMS resonator with a dual-cosine structure for in-plane flexural modes.
• Utilized capacitive transduction and standard SOI manufacturing processes.
• Investigated device characterization under BSE, including temperature effects, electrostatic sensitivity, and noise floor.

Main Results:

• Achieved multi-mode operation at modest frequencies (~300 kHz) without MHz requirements.
• Demonstrated a single mode as a sensor with 39.6 mV/V sensitivity and 1.9 μV/√Hz noise floor.
• Utilized sum frequency of two modes for stable reference (1.5 ppb at 1000s) and achieved long-term stability (11.9 ppb at 1000s) under disturbances.

Conclusions:

• The novel MEMS resonator successfully integrates dual-mode sensing and referencing capabilities.
• The BSE scheme effectively induces nonlinear mode coupling for enhanced performance.
• This work overcomes fundamental limitations, paving the way for advanced integrated microsystem applications.