RF MEMS Switches With RuO2-Au Contacts Cycled to 10 Billion Cycles

We present improvements in RF microelectromechanical switch design and fabrication that demonstrated improved lifetimes in cycled switches. First, implementation of RuO2-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 RuO2-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 RuO2 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.