Contact reliability improvement of a poly-SiGe based nano-relay with titanium nitride coating

This work reports a TiN coated contact implemented in a vertically actuated SiGe-based Nano-Electro-Mechanical (NEM) relay. It is shown that covering the bottom of the movable SiGe beam (the armature) with a TiN layer in the contact region will improve the contact performance of the relay with lowering the on-resistance, R
_ON
, by around 4 orders of magnitude and by enhancing the number of switching cycles without degradation. This NEM relay provides an optimal combination of small motional volume (~0.02μm
³
) and long mechanical lifetime (> 10
¹⁰
in vacuum). Furthermore, with a total contact area of 0.01μm
²
(among the smallest reported so far), an on-resistance of ~1MΩ has been achieved.