Simulation of Stress Effects on Mode-Matched MEMS Gyroscope Bias and Scale Factor

This paper presents a system level MEMS gyroscope simulation technique analyzing the effect of stress on MEMS gyroscope zero rate output (ZRO) and scale factor (SF). A circuit simulation environment that includes the parameterized behavioral models of the MEMS devices is used for predicting the stress effects on gyroscope output. The simulations show that typical packaging stress values (2MPa) create on the order of degrees/hr bias shifts that can limit the gyroscope performance. Drive comb gap mismatches as a result of different stator and rotor displacements due to stress are responsible for the ZRO, and they create a Coriolis in-phase force that cannot be distinguished from the rotational rate signal.