Film resistance and constriction effect of current in a contact interface

A computer simulation based on the finite-element method was used to study the conductance of a contact interface, and the property of conductance was investigated using a global model of contact. The contact interface of the model consists of real contact part with the area fraction f and noncontact part (gap) with the area fraction 1-f. This conductance was computed against f. It was made clear that a great deal of current can flow through a small real contact area (current constriction effect) and hence the conductance does not decrease until f becomes close to zero. The increase of film resistance of the real conducting area is taken into account and the behavior of the contact conductance is studied. The decrease of constriction effect is quantitatively shown and discussed with respect to the increase of film resistance.>