After decades of progress, the speeds of microprocessors stalled around the early 2000s at 3GHz to 5GHz, mainly because silicon is reaching its physical limits. Carbon nanotubes, by contrast, can operate as transistors (or tiny electrical switches) at dimensions smaller than 10 nanometers, or 10,000 times thinner than a strand of human hair. That’s well below the size of today’s leading silicon technology (14 nanometers).
But those nanotubes are like spaghetti, and they have to be marshaled and controlled precisely to function as electronic circuitry. The contact points for the nanotubes create a lot of electrical resistance, which hinders overall performance. IBM has developed a novel way, at the atomic level, to weld — or bond — the metal molybdenum to the ends of carbon nanotubes to create a completely new contact structure.
Using this approach, the researchers in Yorktown Heights, N.Y., demonstrated the smallest contacts for carbon nanotubes at 9 nanometers, where the performance did not suffer despite the tiny dimensions. IBM’s carbon nanotube results satisfy the contact requirement all the way up to the 1.8-nanometer node (four technology generations of manufacturing technology away), showing that the technology can scale sooner than the industry thinks, IBM said.