PORTLAND, Ore. Carbon nanotubes outperformed copper interconnects at the 45-nm process node, according to Rensselaer Polytechnic Institute researchers.
In what is billed as the world's first supercomputer simulation to include detailed quantum mechanical effects, the New York state researchers concluded that the ideal performance of copper interconnects cannot be met at 45 nm and smaller sizes. The reason, they said, was excess heat generation.
By switching to carbon nanotube interconnects, the heat problem was solved, they added.
"We believe that carbon nanotubes at 45 nanometers will outperform copper nanowires," said professor Saroj Nayak. "We have a road map for accurately comparing the performance of copper wires to carbon nanotube wires."
The detailed quantum mechanical simulation relied on RPI's Computational Center for Nanotechnology Innovations, which houses more than 100 teraflops of supercomputer power.
The researchers recommended using bundles of carbon nanotubes for on-chip interconnections to lower resistance and hence decrease the power budget for chips at 45 nm and lower. Few chip makers have anticipated the need for carbon nanotube interconnects at 45 nm, according to Nayak, because they were unable to simulate the precise details of copper's performance at the subatomic level. As a result, other simulations have underestimated the heat generated by copper interconnects.
"To obtain the most complete, reliable data possible," said Nayak. "it is essential that we solve problems with quantum mechanics."
Nayak said he still lacks a way to mass produce carbon nanotube interconnects, which so far have only been fabricated in one-off experiments using methods not suitable for a production environment. Among the outstanding issues are how to precisely place the tiny 1-10 nanometer tubes and how to sort metallic nanotubes--which are good for interconnects--from semiconducting nanotubes, which are good for making transistor channels.
Funding for the carbon nanotube research was provided by the New York State Interconnect Focus Center.