Large lateral contact stiffness on Si nanopillar surfaces

Abstract

We studied the lateral contact stiffness (kcontactx) between the tip of a frictional force microscope and a pillar surface to identify the sliding behavior of the tip at the submicrometer scale. The kcontactx and mean lateral force (⟨F⟩) were systematically measured as functions of pillar diameter φ. We found that the kcontactx on a single Si pillar surface increased whereas the ⟨F⟩ rapidly decreased as φ decreased from the micrometer to the nanometer scale. This contradiction could be explained by the change in tip behavior from dynamic sliding to static sticking.