Abstract

As part of the three-year FFG Bridge research project RESONANCE, the potential of polycrystalline materials—including polycrystalline silicon (PCSi), silicon carbide (PCSiC), and diamond (PCD)—was investigated for use as resonator materials in high-precision MEMS timing devices. The project successfully identified device geometries that minimize anchor and fluidic losses under vacuum conditions, enabling the targeted study of intrinsic energy dissipation mechanisms. It was shown that larger grain sizes enhance both the Young’s modulus and quality factor (Q). In the case of PCD, stochastic modeling proved essential for understanding the dynamic behavior of the resonators. Material development focused on controlled variation of grain size and doping levels, validated through X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS). Specialized dry etching processes were developed to enable the micromachining of PCD and PCSiC. Combined with laser Doppler vibrometry and white-light interferometry, these methods provided detailed insights into the resonance frequency dependence and loss mechanisms of various resonator designs. By successfully applying photothermal actuation and detection, the project was able to eliminate the need for more complex integration of piezoelectric actuators—while simultaneously improving the interpretability of the results.

The project established a characterization-based platform for analyzing energy dissipation mechanisms, thus making a significant contribution to the future development of MEMS-based timing devices using polycrystalline materials. The platform is currently being further developed and expanded in follow-up projects.

Publications

Journal artikles

1. Gesing, Andre, et al. "The gas-liquid-Q-factor-inversion in MEMS plate resonators." Journal of Sound and Vibration 559 (2023): 117777, https://doi.org/10.1016/j.jsv.2023.117777
2. Huber, Dominik, et al. “Tailored measurement setup for the contactless characterization of MEMS resonators at the wafer level”, Journal of Sensors and Sensor Systems (JSSS), (2025)

Conference contributions

1. Huber, Domnik, et al. “Simultaneous Analysis of Local Device Layer Thickness and Film Stress on Cantilevered MEMS Structures”, Sensor and Measurement Science International (SMSI), 2025
2. Huber, Dominik, et al. "Impact of Grain Size on The Q-Factor of Poly-Crystalline Diamond Mems Resonators." 2024 IEEE 37th International Conference on Micro Electro Mechanical Systems (MEMS). IEEE, 2024, https://doi.org/10.1109/MEMS58180.2024.10439421 

Master Theses

1. Gülly, M., Out-of-plane excitation of MEMS resonators in the MHz range with a planar electrostatic transducer arrangement, Diploma Thesis, Technische Universität Wien, 2024, https://doi.org/10.34726/hss.2024.116400
2. Schallert, C., Contactless characterisation of polycrystalline thin-film MEMS resonators with varying layer-thickness on wafer level, Diploma Thesis, Technische Universität Wien, 2024, https://doi.org/10.34726/hss.2024.115166
3. Jurekovic, P., Impact of nitrogen doping on the electrical resistivity and Q-factor of polycrystalline 3C-SiC MEMS resonators, Diploma Thesis, Technische Universität Wien, 2024 https://doi.org/10.34726/hss.2024.110560 

Funding

• Austrian Research Promotion Agency (FFG) -  Bridge (project number: 888041)

Industriepartner

• CarbonCompetence GmbH