Influence of copper on the catalytic carbon nanotube growth process

For Cu/carbon nanotube(CNT) hybrid interconnect technology the growth of CNTs on a conductive substrate connected to Cu lines is required. CNTs were grown by catalytic chemical vapour deposition and the effect of a Cu layer beneath was investigated. By electron energy loss spectroscopy (EELS) we found the Cu to diffuse into the catalyst. This influences CNT growth. Therefore, incorporation of a sufficient diffusion barrier between the Cu layer and the substrate is required. As diffusion barriers we used Ta and TaN.