Thermal and topological characterization of Au, Ru and Au/Ru based MEMS contacts using nanoindenter

This paper reports the comparisons between several pairs of contact materials for micro switches. This study is done with a new methodology using a commercial nanoindenter coupled with electrical stimulation of test vehicles specially designed. The stability of the contact resistance, when the contact force increases, is studied for contact pairs of soft (Au/Au contact), harder (Ru/Ru contact) and mixed material configuration (Au/Ru contact). An enhanced stability of the bimetallic contact Au/Ru was demonstrated considering the sensitivity to power increase, and related topological modifications of the contact surfaces.