Pulsed laser deposited coatings for stiction and wear reduction in MEMS devices

摘要

A wide variety of thin layer coatings have been reported for inhibiting the occurrence of post-release stiction in MEMS. Hydrophobic coatings such as self-assembled monolayers perform this function very well, but have a limited lifetime due to eventual generation of wear-induced damage. On the other hand, metallic oxides with superior wear resistance are hydrophilic in character, making them prone to stiction in humid environments. This paper describes the investigation of several dielectric materials as potential candidates for hydrophobic coatings with good wear resistant properties. Films were grown using a combination of vacuum deposition techniques, including enhanced variations of pulsed laser deposition. Contact angle and hardness measurements were performed on flat single crystal wafers for evaluation of film properties, and initial trials on a lateral friction test structure developed at Sandia National Laboratories were performed.