Carbon nanotube array vias for interconnect applications

The material and electrical properties of the CNT single vias and array viasgrown by microwave plasma-enhanced chemical vapor deposition were investigated.The diameters of multiwall carbon nanotubes (MWNTs) grown on the bottomelectrode of Ta decrease with increasing pretreatment power and substratetemperature while the effects of the growth power and methane flow ratio areinsignificant The decrease of CNT diameters leads to the decrease of the CNTvia diode devices. The increase of growth power enhances the CNT graphitizationdegree and thue the conductivity of CNT via diode devices. In the same viaregion, the MWNT diode resistances of the array vias are lower than those ofthe single vias. The MWNT diode resistances on the bottom electrode of titaniumare lower than those on the bottom electrode of tantalum. It may be attributedto the smaller tube diameters on the bottom electrode of Ti and the workfunction difference between Ta and Ti films with respect to the work functionof CNTs.