Friction and pull-off force on silicon surface modified by FIB

Abstract

The friction and adhesion forces have been measured for silicon surfaces with various patterns having cyclic asperity. The patterns are created by using a focused ion beam (FIB) to mill ditches and to deposit platinum mounds. To study the effect of cyclic asperity on the forces, the friction and pull-off forces have been measured between the pattern and a flat, square scanning probe (0.7 μm × 0.7 μm) of an atomic force microscope (AFM). Both the friction and pull-off forces decrease as the asperity increases (i.e., as the ditch depth or mound height increases). The friction force is proportional to the pull-off force, which indicates the importance of reducing the adhesion force when devising lubrication methods for micromachines and microelectromechanical systems (MEMS).