An ultra-stable MEMS resonator with ±14 ppb frequency stability realized by nonlinearity-mediated drift suppression

Silicon-based MEMS resonators have shown promising potential to replace quartz crystal resonators in many fields, especially in realizing precise timing. However, the large temperature-dependent properties of single-crystal silicon render the MEMS resonators suffer from severe degradation in frequency stability caused by temperature variation, thus hindering the development of silicon-based resonant devices. Although oven-controlled MEMS resonators have been demonstrated to achieve ppb-level frequency stability, the on-chip oven control scheme requires a redesign of the resonator structures or even a change in the manufacturing process, offering little post-fabrication flexibility and limiting its engineering applications. In this work, a nonlinearity-mediated temperature compensation scheme is proposed with the objective of rapidly and precisely controlling the frequency stability of the MEMS resonator. By employing the nonlinear amplitude-frequency dependence of a Duffing resonator to actively suppress the frequency drift after the first stage oven control, the reported MEMS resonator exhibits a frequency stability of ±14 ppb.