Growth of Multiwall Carbon Nanotubes on Nickel-silicide Layers by Using Plasma-enhanced Chemical Vapor Deposition (P-CVD)

Abstract

By using plasma-enhanced chemical vapor deposition (p-CVD), we grew vertically aligned multi-walled carbon nanotubes (CNTs) directly on a nickel-monosilicide layer, without any catalysts other than a metal-silicide layer. The results we obtained are quite important for practical application of CNT vias formed directly on nickel-monosilicide (NiSi) layers, which form the source, drain, and gate region of metal-oxide-semiconductor field-effect transistors (MOSFETs). By using a nickel-silicide layer as a catalyst, the nanotube diameter became smaller than that obtained with a nickel film catalyst. We have also clarified the possibility that CNT diameter can be controlled by forming various Ni-silicide phases such as Ni₂Si, NiSi and NiSi₂. We suggest that Ni-silicide composition plays an important role in controlling the diameter of the nanotubes. These results will enable us to fabricate CNT vias for future LSI interconnects.