Accurate analytical model for air damping in lateral MEMS/MOEMS oscillators

We report on an analytical model for the air damping of laterally oscillating MEMS and MOEMS following up on our recent paper [1]. It can be used to more efficiently design micromechanical devices with tailor-made Q-factors for specific applications. The surface force responsible for the air damping was divided into contributions which were investigated separately. These include squeeze-film damping and the viscous forces responsible for shear wave emission and Couette type flow. Since the squeezing part is mostly underestimated in the current models, we applied more appropriate boundary conditions during the solution of Reynold's lubrication equation. The viscous contributions were investigated with respect to how holes - due to fabrication process or readout - in the moving plate affect the damping. We tested this model against FVM computations (OpenFOAM) and measurements of MOEMS test devices. It was in good agreement with both.