Micromechanisms of fatigue in polysilicon MEMS structures

This paper presents the results of a combined experimental and computational study of crack nucleation and surface topology evolution during the cyclic actuation of polysilicon MEMS structures. The evolution in surface topology observed during the crack nucleation stage is related to the underlying notch-tip stress distributions calculated using finite element analysis. Measured changes in surface topology due to the stressassisted dissolution of silica are shown to be predicted by linear stability analysis.