Nanoscale displacement measurement of electrostatically actuated micro-devices using optical microscopy and digital image correlation

Recent progress achieved in the fields of micro and nanoelectromechanical systems demands a reliable method for high resolution characterization of electrostatically actuated devices. This paper presents a study on optical detection of nanoscale displacements using digital image correlation (DIC) algorithms, commonly used in characterization of in-plane displacements. Optical images of an electrostatically actuated micro electromechanical systems (MEMS) device were processed using a modified drift corrected DIC (DC-DIC) algorithm and the results were analyzed. Using the DC-DIC, the resolution was enhanced significantly and displacement measurements with nanoscale accuracy were captured using standard optics and processing tools. The present study provides a simple and reliable technique for optical characterization of rigid body nanoscale displacements of micro devices.