Towards a Better CMOS-MEMS Resoswitch Using Electroless Plating for Contact Engineering

This work demonstrates a performance enhancement technique for both reliability and sensitivity using electroless plated contact for CMOS-MEMS based resoswitches with a factor of ~7× increase in cycle counts, from ~3×10
⁶
to 2.2×10
⁷
cycles, and shows integrity of the output voltage waveform—the initial and last cycles of output signal are almost the same, indicating an enhancement in the lifetime and signal stability of resoswitches. In addition, electroless nickel plating achieves the sub-micro gap spacing 0.1 μm and 3× decrease in the signal level, from 900 mV
pp
to 300 mV
pp
required for launching hot switching. In particular, applying electroless nickel plating on released CMOS-MEMS folded-beam comb-driven resoswitches to replace the two only contact materials of aluminum and tungsten available in standard CMOS yields not only a much reliable contact but also a reduced gap spacing in the same time.