Contamination Thresholds of Pt- and RuO₂-Coated Ohmic Switches

Micro- and nano-mechanical switches are being considered as complements to solid state transistors. While several different device designs may satisfy performance requirements, contact reliability due to hydrocarbon contamination remains a critical concern in each. This issue can be addressed by identifying contact materials and environments that optimize immunity to contaminants. Here we demonstrate that RuO2, a conducting oxide, does not exhibit contaminant-induced degradation at up to 130 parts per million (PPM) benzene in a nitrogen/oxygen background, and experiences minimal electrical resistance rise at 1,300 PPM. In comparison, Pt-coated switches degrade significantly at only 0.02 PPM benzene contaminant level in nitrogen background. This paper establishes that a proper selection of materials and environment is a promising path toward achieving reliable micro- and nanoswitches.