Effect of levitation forces on the performance of surface micromachined MEMS gyroscopes

In this paper, we study the effect of electrostatic levitation forces on the performance of a MEMS surface micromachined gyroscope. An error model relating the effects of the induced levitation deflections to scale factor and cross axis sensitivity is presented. Simulation and experimental results on a surface micromachined test structure are used to identify deflection versus voltage characteristics. These characteristics are scaled based on typical gyroscope parameters and the findings are that levitation forces can cause more than 50% reduction in scale factor and more than 0.1% increase in undesirable cross-axis sensitivity.