Abstract

The development of full displacement field measurements as an alternative to the optical lever technique to measure the mechanical response for microelectro-mechanical systems components in their environment calls for a modeling of chemically-induced mechanical fields (stress, strain, and displacements). As these phenomena usually arise from species adsorption, adsorbate modification or surface reconstruction, they are surface-related by nature and thus require some dedicated mechanical modeling. The accompanying mechanical modeling proposed herein is intended to represent the chemical part of the system free energy and its dependence on the surface amount. It is solved in the cantilever case thanks to an asymptotic analysis, and an approached closed-form solution is obtained for the interfacial stress field. Finally, some conclusions regarding the transducer eficiency of cantilevers are drawn from the energy balance in the accompanying model, highlighting the role of surface functionalization parameters in micromechanical sensors engineering.

Keywords

cantilever sensors, MEMS, surface strains, surface coupling, variational formulation

Authors