Design and fabrication of a gold electroplated electromagnetic and electrostatic hybrid MEMS relay

This paper reports on a gold electroplated hybrid microrelay that combines the advantages offered by electromagnetic and electrostatic actuation mechanisms. The microrelay design achieves signal by out-of-plane motion of a contact cross-bar fabricated on a diaphragm fixed at both ends to short the isolated input and output contacts. Major factors influencing the design approach include low contact resistance in the closed state, high signal isolation in the open state, latching upon loss of power, and fabrication robustness and cost. The MEMS device is surface micromachined with structures fabricated by electroplating gold through photoresist masks. Experimental results show that 95% of the devices can be actuated and $≈50%$ of them pass signal. The average contact resistance is about $170mΩ$ and the system isolation is $70dB$ at $20MHz$ when a gold ground plane is added.