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Fabrication imperfections strongly influence the functioning of Micro-Electro-Mechanical Systems (MEMS) if not taken into account during the design process. They must be indeed identified or precisely predicted to guarantee a proper compensation during the calibration phase or directly in operation. In this work, we propose an efficient approach for the identification of geometric uncertainties of MEMS, exploiting the asymptotic homogenization technique. In particular, the proposed strategy is experimentally validated on a MEMS filter, a device constituted by a complex periodic geometry, which would require high computational costs if simulated through full-order models. The complex periodic structure is replaced by an equivalent homogeneous medium, allowing a fast optimization procedure to identify imperfections by comparing a simplified analytical model with the experimental data available for the MEMS filter. The actual over-etch, obtained after the release phase, and the electrode offset of a fabricated MEMS filter are effectively identified through the proposed strategy. [ABSTRACT FROM AUTHOR]

This paper investigates different topologies of springs used to couple the orthogonal translational motion of proof masses in Micro-Electro-Mechanical Systems (MEMS). This type of coupling is a key issue, since the dynamic response, and hence, the performance of various devices (e.g., MEMS gyroscopes) critically depends on the mechanical behavior of such deformable components. We first analytically investigate the problem through a model based on a modified second-order Timoshenko beam theory developed for both compact and built-up section beams. Its predictions inspire the design of three test structures, whose purpose is to highlight, through different spring topologies, the transition from a hardening behavior to a softening behavior, with possible intermediate optimum conditions for linear response at large displacements. The structures are characterized in detail, with variable forced displacements at resonance (25 kHz) up to about $10~\mu \text{m}$. Experiments validate the model predictions in all the considered situations. [2018-0181] [ABSTRACT FROM AUTHOR]

Micro-Electro-Mechanical Systems (MEMS) gyroscopes are inertial sensors for the measurement of angular rates. They have a variety of applications from consumer electronics to drones and the need of stability against environmental fluctuations, such as temperature, is a key factor in order to avoid expensive calibration procedures. Frequency Modulation (FM) has been recently proposed as an innovative working principle for MEMS gyroscopes and as the desired solution in terms of stability against environmental fluctuations. In this paper, the FM working principle is formalized for the three-axial case for the first time and the governing equations are derived both in the idealized case of a point-mass gyroscope and in the real case of a distributed-mass gyroscope. Moreover, the mechanical structure of the first three-axial MEMS FM gyroscope is proposed and studied. Preliminary experimental measurements prove the validity of both the model and the simulations results employed during the design process. The proposed structure overcomes lots of the constraints of the surface micromachining fabrication processes and represents an important step towards the development of a new class of MEMS gyroscopes. [ABSTRACT FROM AUTHOR]

The dynamic behavior of a torsional microresonator is characterized analytically, numerically and experimentally both in the linear and nonlinear regime. Starting from the work presented in [1] , here, the highly nonlinear regime is considered and the dynamic pull-in is experienced. Very good agreement between experimental data and numerical model is found also when the analytical methods usually employed to describe the nonlinear dynamic behavior of MEMS (multiple scale methods) are no more accurate. Finally, a numerical limit domain for the microresonator safe operation region in terms of bias and actuation voltages is computed and validated with experimental data. [ABSTRACT FROM AUTHOR]

This paper reports the theoretical and experimental characterization of a new z-axis silicon resonant micro accelerometer fabricated by the THELMA © surface micromachining technique, characterized by differential sensing and very small dimensions. The working principle of this device is based on the variation of the electrostatic stiffness of two torsional resonators. This work is a prosecution of the research on resonant accelerometers published in [1,2] . [ABSTRACT FROM AUTHOR]

The paper analyzes the nonlinear dynamic response of microresonators. A simple physical model of a single span beam axially constrained at both end, possibly with elastic constraints, is considered as representative of different common layout of microresonators. An analytical model, based on the Hamilton's principle, accounting for large displacements is presented and validated thanks to numerical finite element analyses. In order to widen the linear operation range of the device an optimal geometry of the resonator is proposed. [ABSTRACT FROM AUTHOR]

Microsystems (or Micro Electro Mechanical Systems, MEMS) are important components of many popular products in the consumer market and are one of the enabling ingredients of incoming industrial revolutions like Industry 4.0 and Internet of Things (IoT). Behind many Microsystems there are important mechanical principles and coupling effects that must be completely mastered starting from the design phase. More sophisticated and smaller devices also imply to consider many non-linear effects that can be strictly related to the mechanical response or to coupled electro-thermo-mechanical phenomena. This paper contains an overview of key mechanical aspects in design and reliability of Microsystems with a particular focus on non-linear dynamics of oscillators in inertial sensors. • State of the art on non-linear mechanical phenomena in microsystems. • Focus of the paper on resonant inertial micro sensors. • Various examples on non-linearities in real cases. • Discussion on future research directions. [ABSTRACT FROM AUTHOR]