Carbon nanotube array vias for interconnect applications

Abstract

The material and electrical properties of the CNT single vias and array vias grown by microwave plasma-enhanced chemical vapor deposition were investigated.The diameters of multiwall carbon nanotubes (MWNTs) grown on the bottom electrode of Ta decrease with increasing pretreatment power and substrate temperature while the effects of the growth power and methane flow ratio are insignificant The decrease of CNT diameters leads to the decrease of the CNT via diode devices. The increase of growth power enhances the CNT graphitization degree and thue the conductivity of CNT via diode devices. In the same via region, the MWNT diode resistances of the array vias are lower than those of the single vias. The MWNT diode resistances on the bottom electrode of titanium are lower than those on the bottom electrode of tantalum. It may be attributed to the smaller tube diameters on the bottom electrode of Ti and the work function difference between Ta and Ti films with respect to the work function of CNTs.

Electrical reliability and breakdown mechanisms in single-walled carbon nanotubes

“…Present copper interconnect technology cannot supply the required current densities without suffering from electromigration and thermomechanical reliability issues. The recent 2009 International Technology Roadmap for Semiconductors (ITRS) [1] suggested that electrically contacted bundles of carbon nanotubes (CNTs) [2] may replace copper at these small length scales because of their high current-carrying capacities, heightened thermal conductivity, and enhanced resistance to electromigration.…”

Carbon nanotubes for next-generation interconnects

“…1 Carbon nanotubes (CNTs) and graphene nanoribbons have emerged as promising candidates for next-generation VLSI interconnects. [6][7][8][9][10][11][12][13] In the search for novel interconnect technologies, no material has aroused as much interest as carbon nanomaterials since the discovery of the CNT in 1991. 14 The excellent electrical, mechanical, and thermal properties 15, 16 of 1D CNTs have made them one of the most promising materials for applications in nano-electronics 6,7,10,17 and micro/nanosystems.…”

“…This large mean free path allows ballistic transport of electrons over a longer distance, resulting in reduced resistivity, while strong atomic bonds 19 provide tolerance to electromigration. 1,9 Meanwhile, higher thermal conductivity compared to Cu makes CNTs suitable for use as tall vias in 3D integrated circuits. 13, 20, 21 We recently 22,23 modified the 2D fluid model of CNTs to include electron-electron repulsive interaction and built a semiclassical 1D fluid model.…”

Carbon nanotubes for next generation very large scale integration interconnects

“…Its mean free path is in micrometer range compared to ~ 40 nm mean free path in Cu. The large mean fee path in CNT allows a ballistic transport over a wider range of micrometers resulting in reduced resistivity, and strong atomic bonds [34] provide tolerance to electromigration [1,9]. Higher thermal conductivity makes the CNT suitable for use in tall vias of 3D ICs [13,35,36].…”

“…Optical interconnects have already been suggested for on-chip integration [3][4][5] but still face serious integration problems. Among newer and novel VLSI interconnection technologies, carbon nanotubes (CNTs) and graphene nanoribbons (GNR) have emerged promising candidates for next generation VLSI interconnects [6][7][8][9][10][11][12]. An excellent review of these technologies has been presented in one of the recent publications of Li et al [13].…”