Constriction resistance of physical simulated electrical contacts with nanofabrication

To establish a relationship between the physical structure of electrical contact boundary and constriction resistance in actual consumer connectors, we fabricated samples that represented the contact-simulated structure. The sample was created on silicon substrates via nanofabrication, and we measured the sample´s electric resistance precisely. In these samples, the physical structure can be designed and fabricated arbitrarily with an electron-beam lithography system, so that the complicated contact structure can be simulated physically. We measured the resistance of a number of samples that had various “contact areas” to observe the effect of the areas on constriction resistance. We found that the observed effect qualitatively agreed with the result of the formula of the Holm theory on constriction resistance. However, the absolute values of the resistance differed from the results of the equation. This is attributed to the fact that the equation is intended for an ideal condition. Under the ideal condition, electrodes are infinitely sized, and at any point, there is zero distance between them. By contrast, in actual contacts, electrodes are finitely sized, and there is some insulator, including air, between them. Our measurements suggest that the constriction resistance of actual contacts can be described by introducing additional parameters into the classical Holm theory.