Electrostatic Tuning to Achieve Higher Stability Microelectromechanical Composite Resonators

Electrostatic tuning of the frequency in micromachined Si-SiO2 composite resonators for temperature compensation is demonstrated and analyzed. Electrostatic tuning exploits the bias voltage dependence of frequency for the compensation. Si-SiO2 composite resonators have intrinsically small frequency variation over temperature, thus being appropriate for electrostatic tuning. We developed a tuning procedure and applied it to a flexural-mode composite resonator. Experimental results show ±2.5-ppm stability over a 90°C-wide temperature range.

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