A system for automatic electrical and optical characterization of microelectromechanical devices

A new optical method for characterizing the performance of microelectromech anical systems (MEMS) is described that is significantly faster and simpler than previously described optical methods. The method uses video imaging u nder continuous illumination to effectively remove the upper limit imposed by other methods on the frequency of motions that can be measured. It can b e used to-measure the motions of any visible structure, whether or not an e lectrical or optical sensor for that motion has been incorporated. The magn itude of the displacement of a target, such as the edge of a sinusoidally v ibrating shuttle mass, is obtained from a single frame of video taken durin g motion plus a reference frame taken when the target is at rest. The speed of this technique facilitates hands-on testing of prototypes and is especi ally attractive for production environments. An automated MEMS microresonat or testbed is described that performs on-line resonance curve parameter ext ractions of resonant frequency (f(0)) and quality factor (Q) from electrica l measurements, which are derived from output comb-drive current measuremen ts using established methods, and from simultaneous optical measurements us ing the new method. Results obtained using these methods for design evaluat ion of microfabricated lateral resonators are discussed, and favorable benc hmark comparisons of the optical results with results from a MEMS testbed a t the Massachusetts Institute of Technology are presented. [432].