Testing of MEMS material properties and stability

This article presents progress in characterizing MEMS failure. The results are applicable to a wide range of materials and applications. Data is presented, however, for MEMS polysilicon and single crystal silicon. The observations of fatigue crack growth in single crystal silicon and time dependent crack initiation in polysilicon are important because they indicate MEMS failure modes that have not been previously recognized. The effects of microstructure, environment, and fabrication can become significant on the micro scale even when they are irrelevant in larger, macroscale structures. The microstructure of MEMS devices is also different from that of large bodies of the same material.