Carbon nanotube-based nanorelays for low-power circuit applications

Abstract

The objective of this research is to reduce static power dissipation by developing a vertically-oriented carbon nanotube-based nanoelectromechanical switch that has no off-state leakage current. This switch, called a nanorelay, is a mechanical switch that uses a carbon nanotube as the active component. The device consists of a line of carbon nanotubes grown on a highly-doped silicon substrate between two contacts that are electrically isolated from the substrate by an insulator. The nanorelay is actuated when a control voltage is applied between the substrate and either one of the contacts. This voltage causes the nanotube to be pulled into and eventually make physical contact with one of the contacts, which allows current to flow through the carbon nanotube. During the off state, a physical gap separates the nanotube from the contact which acts as a near-ideal tunneling barrier to virtually eliminate leakage currents. Since the nanorelay has almost no static power dissipation, it has many potential applications in low-power circuit design. This thesis makes three main contributions. First, a fabrication process to construct nanorelays is presented. Second, potential low-power circuit applications of the nanorelay are explored and implemented in a CMOS test chip. Finally, a test system is developed in order to characterize and quantify the static power savings benefits of using the nanorelay for low-power circuit applications.