Abstract
To practically realize high precision processes and devices based on scanning nanoprobes, it is required to improve not only the wear durability of the probe tip but also the electric contact stability at the sliding probe electrode. It has been known that the native oxide film covering the electrode surface has a significant effect on electric contact and wear behavior, but its effect was not clearly understood.
In this study, we examined in detail the influence of the surface oxide film on the relations between electric contact resistance and wear at the nanoscale sliding contact area by using a scanning probe microscopy system. It was confirmed that the electric current could be enhanced by the tunneling current passing through the relatively thin part of the oxide film. Meanwhile, when the probe slid on the conductive indium tin oxide film for a long distance, the electric contact resistance gradually increased and finally the electric current was lost. This implies that the wear debris of the oxide film adhered to the probe tip and that it formed a covering layer, which reduced the tunneling current. It is also suggested at the same time that the covering layer helped to improve the wear durability of the probe tip.
