RF MEMS Switches With $\hbox {RuO}_{2}$ – $\hbox {Au}$ Contacts Cycled to 10 Billion Cy

We present improvements in RF microelectromechanical switch design and fabrication that demonstrated improved lifetimes in cycled switches. First, implementation of $\hbox {RuO}_{2}$ – $\hbox {Au}$ contact metallurgy into an existing design showed improved switch lifetime over switches with Pt-Au, Ir-Au, and Au-Au contacts. Second, the switch design was changed to reduce impact upon switch closure, and the fabrication process was changed to avoid the use of polymer sacrificial materials while including the $\hbox {RuO}_{2}$ – $\hbox {Au}$ contact metallurgy. Switches with the new design were cycled to 10 billion cycles with a resistance less than 4 $\Omega$ , an insertion loss of 0.4 dB, and an isolation of 28.0 dB at 10 GHz. We propose that the catalytic behavior of the $\hbox {RuO}_{2}$ film prevents or delays the failure of the switches due to accumulation of carbon at the contacts. Additionally, the reduced impact upon closure prevented significant contact evolution during cycling. $\hfill$ [2012-0205]