Hints of atomic scale phenomena in adhesion and friction measurements with MEMS devices

Abstract

Friction and wear on the nanometre scale currently hamper the use of microelectromechanical system (MEMS) devices with sliding surfaces. Based on the friction force microscope principle, we have developed MEMS devices that can be used to probe the tribological phenomena taking place in MEMS. We find that several measurements hint towards atomic scale processes that are relevant on the MEMS scale, even though MEMS themselves are much larger than atomic dimensions. The reason is that the tribological properties of MEMS devices originate from the phenomena taking place on the nanometre scale between the contacting/sliding rough MEMS surfaces. We have observed stochastic variation in the adhesion between oxygen plasma cleaned MEMS surfaces, and slow creep in MEMS contacts, both hinting at atomic scale processes that need to be understood to further complete our picture of MEMS adhesion, friction and wear.