Sub-5 nm gap formation for low power NEM switches

To utilize nanoelectromechanical (NEM) switches for ultra-low power applications, sub-1 V actuation is one of the most important challenges to overcome [1-4]. We develop a CMOS-compatible technique that introduces ultra-small air gaps ( bg ) is 0.25 μm, and the gap between the beam and the drain (g bd ) ranges from 1 to 40 nm. Fig. 1b shows that for g bd bg , the pull-in voltage of the NEM switch decreases efficiently by shrinking g bd . In order to obtain sub-1 V switching, the contact gap g bd has to be minimized to sub-5 nm, which is difficult to achieve in the lateral NEM structure using a “top-down” pattern-and-etch approach.