Characterization of structural films using microelectromechanical resonators

ABSTRACT Micromachined resonant fatigue characterization structures have been used by a variety of investigators to evaluate the stress‐life fatigue behaviour of thin films. This work will review the design, testing and analysis of these versatile thin‐film characterization structures. Subsequent discussion will illustrate how this material characterization approach has been used to evaluate the high‐cycle fatigue behaviour of silicon films commonly used in microelectromechanical systems (MEMS). This work demonstrates that properly designed resonators can be used to monitor extraordinarily low fatigue crack growth rates (i.e. ≪ 10−10 m/cycle) relevant to these minute mechanical components.