In situ characterization of induced stiction in a MEMS

Stiction remains a limiting factor in the performance and lifetime of MEMS devices. We have developed experimental tools for inducing and quantifying changes in stiction on a large array of MEMS actuators. Thousands of elements were subjected to aggressive wear in order to produce shearing forces that contributed to the degradation of contacting surfaces. Custom electronics were developed to accomplish nonstandard actuation of the MEMS array. Optical techniques were used to characterize the induction of and progression of stiction. A model incorporating experimental and geometrical values was used to determine stiction force as a function of actuation duration and packaging. For a depackaged array, an increase in stiction force of ∼230 nN (per element) was induced through three days of high-speed actuation.