Until now, as nanotube based devices become smaller, increased contact resistance has negated any performance gains. These results could overcome contact resistance challenges all the way to the 1.8nm node – four technology generations away.
“For any advanced transistor technology, the increase in contact resistance due to the decrease in the size of transistors becomes a major performance bottleneck,” said Dario Gil, vice president of Science and Technology. “Our approach is to make the contact from the end of the carbon nanotube, which we show does not degrade device performance. This brings us a step closer to the goal of a carbon nanotube technology within the decade.” IBM has previously shown that carbon nanotube transistors can operate as excellent switches at channel dimensions of less than 10nm.
Until now, decreasing the size of the contacts on a device caused a commensurate drop in performance – a challenge facing both silicon and carbon nanotube transistor technologies. To solve the problem, IBM’s researchers invented a metallurgical process akin to microscopic welding that binds metal atoms chemically to the carbon atoms at the ends of nanotubes. This ‘end-bonded contact scheme’ allows the contacts to be shrunken beyond 10nm without affecting the performance of carbon nanotube devices.
