Analysis of intrinsic damping effects and development of design rules for enhanced robustness of high-Q micromechanical systems

• Applicants: Professor Dr.-Ing. Jan Mehner; Dr.-Ing. Danny Reuter
• Subject Area: Microsystems
• Term: since 2025
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 545127749

The quality factor is a central parameter for highly resonant micromechanical systems, which decisively determines both the dynamics and the sensitivity. The effects of fluid structure interactions related to MEMS have been extensively explored in the past. The ever-increasing requirements on micromechanical systems in terms of achievable sensitivity coupled with ongoing miniaturization leads to an increasing importance of material-intrinsic loss processes for resonant MEMS sensors and actuators. This in turn requires an ever deeper understanding of the associated effects and interactions, since material-intrinsic damping has not yet been controllable in terms of a design in the desired target corridor. The aim of the project is to analyze material-intrinsic mechanical losses, to investigate their causes and possible influencing factors and to evaluate their effects on the function and robustness of the MEMS. The focus is on clamping losses and related coupling effects in low-frequency capacitive MEMS (eigenfrequency less than 200kHz), as well as defect-induced losses, which are commonly assumed to be mainly caused by fabrication. Furthermore, the thermoelastic effect must be considered, which occurs as another intrinsic loss mechanism in addition to the two aforementioned ones. In the project is planned to utilize experimental characterization of test structures to achieve an assessment of the occurrence, dominance and variance of the damping effects. For this purpose, the influences of different designs of test structures as well as adapted manufacturing technologies and their impact on the variation of the loss effect are examined. In addition to the experimental characterization, numerical methods are used to parametrically model the effects of slight asymmetries on the dynamic behavior of the structures. Finally, the knowledge gained is used to derive modelling, design and manufacturing strategies for systems with high quality-factors (high-Q). In addition, a contribution will be made to the targeted and robust design of micromechanical systems with a material-intrinsically dominated quality factor.

• DFG Programme: Research Grants