Mechanical Characterization of Electrostatic MEMS Switches

This paper presents a methodology developed to characterize the mechanical properties of MEMS switches. Mechanical experiments have been performed to explain the electrostatic behavior of an ohmic electrostatic series switch made by CEA-LETI. The mechanical properties of switches are characterized by nanoindentation experiments : membrane stiffness, gap heights and contact load. These results have been compared to the results obtained by simple analytical models : the mechanical model shows a good correlation with a membrane stiffness currently around 50-100 N/m, and the electrostatic model gives capacitance values in accordance with measurements. Based on these results, the electrostatic behavior of switches has been analysed : the influence of the mechanical properties on the ohmic and capacitive responses is pointed out.