Electrostatically Driven Nanoelectromechanical Logical Gates Utilising Selective Tungsten Chemical Vapor Deposition

Abstract

This paper presents the design, fabrication, and evaluation of electrostatically driven nanoelectromechanical (NEM) switches and logical gates, including NAND and NOR gates. The conformal deposition of tungsten (W) on high aspect ratio structures is investigated by selective W chemical vapor deposition (CVD) as an electrical contact material. The switching characteristics of the NEM switches, as well as their pull-in voltages, are evaluated. Logical gates, including NAND and NOR gates, are formed by the four NEM switches consisting of four cantilevers, two input ports, two source ports, and an output. Devices are successfully fabricated by a combination of an electron beam lithography, a deep reactive ion etching, and a selective W CVD. The truth table operations for the NAND and NOR gates are examined and demonstrated in this paper.