Carbon, Better than Copper at the 45-Nanometer Scale

Rensselaer Polytechnic Institute researchers have released a report claiming that carbon nanotubes are better than copper interconnects when performing at the 45-nm process node.

The scientists used for the first time a supercomputer simulation with detailed quantum mechanical effects, which shown that copper cannot perform ideally at the 45-nanometer node or smaller technologies. This is mainly because copper interconnects generate excessive heat, which increases the conductor's resistivity, thus requiring more electrical energy.

However, carbon nanotubes can address the overheating issue and are the best alternative to copper nanowires when going below the 45-nanometer semiconductor technologies.

"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 mechanical simulation was performed at the RPI's Computational Center for Nanotechnology Innovations, that can deliver more than 100 teraflops of effective computing power. According to the scientists, carbon will be used in bundles in order to create low-resistance on-chip interconnections. That will dramatically reduce power consumption at the 45-nanometer node.

According to Nayak, copper nanowires are still used in the 45-nanometer technology because there were only a few chip manufacturers to have anticipated the advantages carbon can deliver over the old-fashioned copper. This could not have happened otherwise, as no researchers could simulate the exact behavior of copper at the subatomic scale.

"To obtain the most complete, reliable data possible, it is essential that we solve problems with quantum mechanics," claimed the researcher.

The greatest obstacle is mass-producing the carbon nanotube interconnects, that could only be manufactured in limited amounts, using controlled-environment conditions. Also, the researchers are currently trying to find suitable methods for sorting the metallic nanotubes (that can act as interconnects) from semiconducting nanotubes, used in transistor channels.