Analysis of shock-induced polysilicon MEMS failure: a multi-scale finite element approach

MEMS can be exposed to shock loadings, since they are often designed for portable devices. We recently investigated the effects of shocks on polysilicon inertial MEMS sensors within the framework of a top-down, uncoupled multi-scale approach, explicitly exploring three length-scales: a macroscopic one (package length-scale); a mesoscopic one (sensor length-scale); and a microscopic one (polycrystal length-scale). In this work we focus on meso-scale analyses, and suggest possible enhancements of their predictive capabilities. Specifically, we discuss: homogenization procedures to upscale (from micro-scale to meso-scale) the mechanical properties of the polysilicon film constituting the movable parts of the MEMS; a reduced-order model to efficiently track the vibrations of the whole MEMS sensor, without resorting to time demanding finite element simulations.