Measurements and analysis of surface potential change during wear of single-crystal silicon 100/ at ultralow loads using Kelvin probe microscopy

The change in surface potential resulting from wear at ultralow loads using Kelvin probe microscopy is studied. Samples studied include single-crystal silicon 100., single-crystal silicon 100. lubricated with fully bonded Z-DOL a perfluo- ropolyether.. The effects of relative humidity RH. as well as that of load and number of cycles during wear on the change in surface potential have been investigated. It is believed that the removal of either contaminant layer, natural oxide layer or lubricant during few wear cycles gives rise to the initial change in surface potential. As the number of cycles andror load increases, the material is removed from the silicon surface by subsurface fatigue wear and stresses beneath the silicon surface resulting in subsurface structural changes which are responsible for further change in the surface potential. q2000 Elsevier Science B.V. All rights reserved