IBM says that its scientists have made a major engineering breakthrough that could help speed the transition from silicon-based transistors to those constructed from carbon nanotubes. Its new discovery, which concerns the two contacts of a transistor, leads IBM to believe that its carbon nanotube technology could scale all the way down to 1.8nm.
With Silicon transistors reaching their scaling limits, carbon nanotubes could be a key material in the production of smaller scale, faster, more efficient processors. IBM sees value in this development in big data analysis, faster mobiles with better battery life and Internet of Things devices.
Two hurdles a transistor must face when scaling down in size are the size of its channel and of its two contacts. IBM previously demonstrated that carbon nanotube transistors can operate as excellent switches at channel dimensions of less than 10nm. Until now it was the contact sizes that were restricting performance gains, and size reductions in complete carbon nanotube transistors. Now IBM has developed a new contact approach to result in smaller chips with lower power consumption.
Decreasing the size of the contacts previously caused a drop in performance, as the contact electrical resistance shot up. A newly developed metallurgical process has overcome this effect. IBM says that Molybdenum is chemically bonded to the ends of carbon nanotube channels to make the contacts in what is called an 'end-bonded contact scheme'. The result is a smaller scale contact that doesn't degrade performance. According to IBM, its contact development, plus its previously demonstrated transistor channel tech, could result in the deployment of carbon nanotube technology transistors within the decade. It is thought that the carbon nanotube transistors will arrive just in time to allow Moore's Law to continue its march.
