Sensitivity enhancement for micromechanical vibro‐impact resonators using snap‐through curved beams

• Published in: Micro & nano letters 2023-01, Vol.18 (1), p.n/a
• Main Authors: Yi, Yun, Tsai, Chun‐Pu, Li, Wei‐Chang
• Format: Article
• Language: English
• Subjects: Actuation; Curved beams; Electric potential; Electrodes; impact (mechanical); microfabrication; micromechanical devices; micromechanical resonators; Resonators; Sensitivity enhancement; Voltage
• ISSN: 1750-0443; 1750-0443
• DOI: 10.1049/mna2.12155

This work enhances the driving sensitivity of micromechanical vibro‐impact resonators by reducing the output switching gap. Differing from previous works for gap narrowing that either require a dedicated pull‐in bias voltage and stopper structures or post‐fabrication refill processes, the use of the snap‐through technique calls for only the initial activation step without the need for constantly applied voltage or additional process steps. Doing so realizes a final gap spacing from a typical 2‐μm limitation to a 0.9‐μm sub‐micron gap. While probes are used to mechanically initiate the bistable transition in this proof‐of‐concept demonstration, this could be done electrically once properly designed actuation electrodes are available. This transducer gap narrowing technique can help facilitate higher sensitivity for vibro‐impact resonator embedded applications such as zero‐quiescent power communication receivers. A gap narrowing technique based on bistable snap‐through curved‐beam for micromechanical air‐gap vibro‐impact resonators is demonstrated to enhance the signal sensitivity of the devices. The technique achieves a gap spacing beyond the minimum feature size achievable by the process used. The results can help facilitate the development of not only vibro‐impact resonators but also generic micromechanical capacitive resonators that require small gaps for high electrical‐to‐mechanical coupling.