The effect of the distribution of α-spots in the peripheral part of an apparent contact point on constriction resistance

The constriction resistance resulting from the constriction of current flow is one of main components in the contact resistance of electrical contacts in connectors. When the current flow has a round-shaped section as a contact point, the constriction resistance can be calculated analytically; however, this is not the case for real contacts. In the apparent contact point between two electrodes, there are many real contact points called a-spots. Even in the apparent contact point, there is no current flow in other part than the a-spots. Thus, the area of apparent contact point is not equal to the total area of a-spots and its constriction resistance cannot be calculated. From some previous studies, it is suggested that the constriction resistance of the contact with a-spots concentrated on a peripheral part of its apparent contact point is lower than that of the other if the total area of a-spots is constant. We fabricated some contact-like-structures on Si chips with various distributions of "a-spots" along the peripheral part of their "apparent contact point" using nanofabrication technology and compared their constriction resistances with each other for examining the relation between the distribution of a-spots and constriction resistance. Our simplified samples have shown resistance values between the calculation results using the Holm's equation and the Greenwood's equation.