Tribol. properties of Si/Si contacts were measured on a microscale by using an at. force microscope/friction force microscope (AFM/FFM). Friction forces and pull-off forces between a Si tip and a polished surface of a Si(100) wafer were studied as a function of applied normal load and relative humidity of the surrounding air. Pull-off forces and friction coeffs. increased and were strongly influenced by capillary forces with increasing humidity. Tribol. interactions during 20 passes of overlapping sliding contact at 50% relative humidity and very small loads of 70nN were confined to the layer of adsorbates and chem. reactions, without measurable solid damage on the Si(100) wafer.