Measurement of MWCNT/Tungsten contact resistance by bridging CNT on two tungsten electrodes with two manipulators

Abstract

Semiconductor nano-devices based on carbon nanotubes (CNTs) have attracted great interests recently such as field effect transistors (CNTFETs). One of the challenges is to reduce the contact resistance between CNT and electrodes. This paper presents a robotic system with two nano-manipulators for two-lead contact resistance measurement. Electron beam induced deposition (EBID) technique was applied to decrease the contact resistance between multi-walled CNTs (MWCNTs) and Tungsten deposition fabricated by focused ion beam (FIB). A Tungsten (W) probe fixed on one manipulator is used to pick up a CNT selectively from a CNT bundle. The picked CNT was positioned to approach a W deposition on an atomic force microscopy (AFM) cantilever. The cantilever mounted on another manipulator was coordinated by positioning for well contact between the W deposition and CNT. To strengthen this contact, four W points are deposited on the contact area of CNT for totally 9min by EBID. A resistance between W probe and cantilever was measured before and after EBID. Based on these measured resistance, contact resistance was calculated by a theoretical model. It showed the contact resistance of MWCNT/Tungsten deposition was reduced by 98.8% by the EBID deposition.