Tribology of Microelectromechanical Systems

The microelectromechanical systems (MEMS) tribology group is located in the Materials Directorate at Wright-Patterson Air Force Base. Our research is directed toward investigating friction and wear mechanisms of MEMS materials and devices.

MEMS technology offers enhanced performance and reduced cost. Coupled with the microscopic nature of the technology, MEMS holds particular promise for aerospace systems by reducing mass. However, the small size of MEMS devices brings surface forces such as adhesion, stiction, and friction into the foreground, and inertial effects are no longer as prominent as in the “macro” world. This thrusts us into the world of micro/nanotribology, which is not well understood.

Areas of research by UDRI include: (1) failure mechanisms of MEMS devices, (2) micro/nanoscale tribology, and (3) low friction and wear-resistant coatings for MEMS. Device-level testing is important because it ensures the relevance of any lubrication scheme to MEMS technology.

We have constructed special equipment and developed experimental methodologies to study friction and wear on the micro and nanoscales, which is necessary to simulate actual conditions within MEMS devices. Our MEMS tribology laboratory is equipped to study failure mechanisms of MEMS devices in aerospace environments. We also have the expertise and facilities for the deposition of organic monolayer lubricating films.

For example, polycrystalline silicon is the most commonly used structural material in MEMS, but it is not a good tribological material. Low friction and wear coatings are being developed in our group to protect polysilicon MEMS, and new structural materials that may have better tribological properties are also being evaluated.