Abstract
A two-dimensional linearized Bhatnagar, Gross, and Krook (BGK) model for the Boltzmann equation has been used to evaluate the damping forces exerted by a gas on the moving surfaces of a micromechanical structure. A very good agreement has been found between our numerical results and the experimental data collected on a silicon biaxial accelerometer in the transitional flow regime. Furthermore, it has been shown that the one-dimensional Reynolds equation fails to predict the squeeze film damping in the two-dimensional structures typical of real MEMS.
The authors thank “FONDAZIONE CARIPLO” for financial support of the research activity within the frame of “Sviluppo di metodi analitici e numerici per lo studio di flussi gassosi rarefatti in micro/nano sistemi elettro-meccanici (MEMS/NEMS)” and the EU “Design for Micro & Nano Manufacture (PATENT-DfMM)” Network of Excellence. Furthermore, the authors thank Benedetto Vigna head on MEMS business unit STMicroelectronics for providing experimental data on the accelerometer.