Creep-resistant nanocrystalline gold-vanadium alloyed microcorrugated diaphragms (MCDS)

This paper presents new microcorrugated diaphragms (MCDs) capable of achieving large displacements (>20 μm) with the lowest reported stress relaxation today. These MCDs are fabricated by co-sputtering of gold (Au) and vanadium (V) followed by a 2-hour annealing at 300 °C. Compared to conventional RF MEMS sputtered Au films, the reported MCDs exhibit a 1.8× and a 10.5× lower stress relaxation rates at the 3rd and the 12th hour, respectively. The developed Au-V films demonstrate more than 50% smaller average grain size than pure Au, excellent process compatibility, and significantly lower stress relaxation rate. As a result, they are very promising in improving reliability issues of widely tuned RF MEMS devices.