Contact resistance of Sn-film and Sn-bulk investigated by microscopic analysis

In order to evaluate the relation between the contact resistance and the microscopic property of electrical contacts, we have proposed the visualization method by means of conductive-AFM. In this study, we mechanically fabricated indentations on Sn-coated-Cu and Sn-bulk plates, and investigated by I-V mapping method. It was found that the conductive points were distributed inside the indentation scar, and the number of conductive points dominate the total contact resistance. Furthermore, we assumed each conductive point as a-spot and attempted to represent the contact resistance from the experimental values and the Holm formula.