CVD grown Graphene Microfilms as a Promising Microscaled Solid Lubricant for the Lubrication of Silicon MEMS Devices

Abstract

Friction, wear, stiction, adhesion, and absence of suitable lubrication methods are important challenges, severely restricting and limiting the expeditious development of Microelectromechanical system (MEMS) technology. This paper aims to explore the potential of chemical vapor deposition (CVD) grown graphene microfilms for the lubrication of sliding silicon MEMS devices to reduce friction and wear problems. A novel silicon-based pin-on-disk friction-pair is designed to mimic sliding MEMS working conditions. Pure graphene-based microfilms are fabricated on the Cu substrate via a CVD method and transferred to the silicon substrate via the PMMA transfer method. To investigate microfilms' surface quality and morphology, microfilms are characterized via Raman spectroscopy, AFM, and SEM. For the tribological performance evaluation, different tribological tests were conducted using the microtribometer. Results show that microfilms remarkably reduced the friction coefficient and wear in the MEMS devices; however, microfilms' tribological performance depends on the roughness and the number of films on the specimen. This remarkable tribological performance suggests that graphene microfilms have the potential to increase the reliability and wear lifespan of MEMS devices. It is foreseeable that this lubrication method can be a step towards the expeditious industrial development of silicon MEMS devices.