Dominant factor of contact resistance analyzed by conductive-AFM

The contact resistance defined by the Holm theory is expressed as the sum of the resistance of each real contact area. Thus actual contact resistance is possible to estimate from number of conductive points and electrical current in each point. However, each real contact area is difficult to distinguish by direct viewing. In this study, we mechanically contacted pin and plate of tin (Sn), and attempted to investigate the relationship between contact load and contact resistance in terms of number of conductive points inside the apparent contact area. We applied conductive atomic force microscopy (AFM), and successfully visualized the distribution of conductive and isolation points. In this paper, we reported the experimental method of I-V mapping and the relationship between contact resistance and number of conductive points.