Contact resistance, stiction force, and field-assisted growth and migration in MEMS and NEMS metals

Measurement and control of stiction force in in-plane electrostatically actuated Si nanoelectromechanical cantilever relays with Pt contacts

“…This value is close to the reported stiction force for Pt contact (F stiction = 50 nN) in NEMS relays (for I DS 10 µA and R DS ∼ 10 kΩ), extracted using experimental I-V hysteresis in electromechanical simulations [24]. Our results also agree with the data reported by Tabib-Azar et al [19], who measured the Pt stiction force between a Pt-coated tip in an atomic force microscope and a Pt thin film to be 65 nN. However, the authors did not report the stiction force dependence on the R DS and/or I DS .…”

“…It is thus necessary to know the strength of the stiction force for appropriate design and operation of N/MEMS relays. Although Pt stiction force has been measured using atomic force microscopy (AFM) [19], it is not entirely applicable to NEMS/MEMS relays since an AFM tip surface guarantees maximum contact with the measuring surface, unlike a source-drain contact in a NEMS/MEMS cantilever relay, where only a few asperities are in actual contact [6,7,13]. Additionally, contributions from retarded vdW forces and metallic bonding forces may not be properly accounted for during stiction force determination using an AFM tip.…”

Review: Electrostatically actuated nanobeam-based nanoelectromechanical switches – materials solutions and operational conditions

“…The reliability of various metals as electrode materials has been examined both theoretically [ 144 ] and experimentally [ 63 , 145 – 152 ] using mechanical [ 145 – 146 ], electrical [ 145 – 146 ] or coupled electromechanical [ 63 , 147 – 152 ] testing experiments. The materials properties such as hardness, wear resistance, melting point, conductivity and oxidation characteristics should be considered for each particular application.…”

“…A W/Cr contact demonstrated the lowest adhesion force, compared to other metals (e.g., Pt and Ni) [ 145 ]. However, for a W contact material, relatively large changes in contact resistance [ 146 ] and degradation of the on state current during cycling [ 49 ] have been reported, which has been attributed to the impact of its native oxide [ 49 , 146 ].…”