IBM thinks carbon nanotubes will defeat Moore’s law

Perhaps Moore’s law isn’t doomed just yet. This overcomes a huge hurdle in shrinking transistor size beyond current limits.

IBM said its researchers successfully shrunk transistor contacts in a way that didn’t limit the power of carbon nanotube devices.

“This is critically important for extending Moore’s law”, Han continued.

A major engineering breakthrough by IBM that uses carbon nanotubes instead of silicon transistors could accelerate the future of computing, particularly areas like internet of things, big data and mobile battery life. “I would argue it’s now more important than the channel [in the efforts to shrink transistors]”.

Schematic showing the fabricated nanotube transistor with an end-bonded contact and a contact length below 10 nm.

The MIT Technology Review notes that viable chips for future high-performance computers would need billions of transistors, and the contacts would have to be a lot smaller. By advancing research of carbon nanotubes to replace traditional silicon, IBM is hoping to pave the way for a post-silicon future and delivering on its $3 billion chip R&D investment announced in July 2014.

“These chip innovations are necessary to meet the emerging demands of cloud computing, Internet of Things and Big Data systems”, said Dario Gil, vice president of science and technology at IBM Research, in a statement.

This means that the size of the semiconductor can decrease dramatically, while the substrate of carbon nanotubes makes the chip more energy efficient and is a soft and flexible material that could allow new device form factors. “There are still a bunch of issues on the materials side”, said Han.

The problem engineers are facing is that the smaller silicon transistor contacts get, the higher their electrical resistance becomes. And with silicon reaching its physical limits, the success of carbon nanotube research will be essential if that trend is to continue.

To overcome the problem, IBM developed an entirely new metallurgical process that chemically binds metal atoms to the carbon atoms at the end of the nanotubes.

IBM has been investing heavily in carbon nanotube research, and has already shown that carbon nanotube transistors can be used as excellent switches at channel dimensions of less than 10nm: “the equivalent to 10,000 times thinner than a strand of human hair and less than half the size of today’s leading silicon technology”, the company explained.

That’s because electrons found in carbon transistors move more efficiently than those that are silicon-based, even as the extremely thin bodies of carbon nanotubes offer more advantages at the atomic scale, IBM says.

This colored micrograph shows several transistors made from a single carbon nanotube. The recent work achieves that. The IBM researchers say they’ve figured out how to overcome one of them: how to combine nanotubes with the metal contacts that deliver electric current. Inside a chip, contacts are the valves that control the flow of electrons from metal into the channels of a semiconductor. Increased electrical resistance in a transistor results in performance reductions, meaning that, until now, smaller contacts would result in slower processors. However, as devices become smaller, increased contact resistance for carbon nanotubes has hindered performance gains until now. Han added that IBM’s breakthrough brings the company a step closer to the goal of a carbon nanotube technology within the decade.