Fabrication and thermal stability characterisation of Ru electrode used for high power contact radio frequency microelectromechanical system switch

Reported are the fabrication and thermal stability of an Ru electrode, which is used for a high power Ru-Au contact radio frequency microelectromechanical system switch with a microspring contact design. In this reported work, a new process with bilayer lift-off and a strain release layer is developed, thereby acquiring the 3000 Å Ti/Au/Ru electrode with excellent smooth edges for high-power handling capacity and low loss. Furthermore, thermal tests under 400, 500 and 600°C for over 1 h have been performed. Investigation of the surface with scanning electron microscopy and energy dispersive X-ray spectroscopy shows that the electrode has a good thermal stability at 400°C, which is proper for high-power handling. The cold switch DC current handling capacity is advanced from <;90 mA per point (failed) to 100 mA per point (still working).