Understanding the Effect of Surface Topography on Stiction and Friction in MEMS

Abstract

While on one hand, the number of smaller, more complex and more useful new MEMS prototypes, which are commercially extremely attractive, is continuously increasing, on the other hand, despite years of research, the Micro-electromechanical Systems (MEMS) community is yet to find a solution that sufficiently addresses the reliability issues (stiction, friction and wear) that limit the commercial success of most MEMS prototypes. The main bottleneck, which limits the ability of the MEMS community to devise an appropriate solution, is their poor understanding of the influence of the factors, especially surface topography, on the tribological behaviour of MEMS surfaces. Therefore, there is a serious and urgent need to conduct a systematic investigation for understanding the effect that the surface topography of MEMS surfaces has on the stiction and friction experienced by them. This study reports the development of test devices that can be used to study the effect of topography of contacting MEMS surfaces on the stiction and friction experienced by them. Details on the design, actuation procedures and modeling of the test devices are provided in this study. Further, the study reports a technique that can be used to controllably tailor the surface topography of the test surfaces. Finally, the study reports the formulation of two mathematical correlations, which can be used to predict the effect that the surface topography of MEMS surfaces has on the stiction and friction experienced by them.