ABSTRACT

This chapter discusses the state of knowledge of nanoscale contacts and the effect on reliability in micro-mechanical switches. When an electromechanical switch closes, contact is made between two metallic surfaces, the circuit is completed, and current is allowed to flow across the interface. The combined area of these contacts is called the real contact area, which is typically orders of magnitude smaller than the nominal contact area. In microswitches the area of each nanocontact is affected by both the applied normal force as well as the force of adhesion. In 1882 Heinrich Hertz presented his well-known theory of contact between nonconforming elastic bodies, which became known as Hertz contact. Nanoscale contacts, such as those occurring in a micromechanical switch, typically are at a scale large enough that continuum theory applies, but small enough that the force of adhesion is significant.