IBM packs 10,000 carbon nanotube transistors onto single chip

Carbon nanotubes may take over from silicon as processors get smaller and more energy-efficient, and IBM has just announced a fresh breakthrough in making the technology viable.

IBM's researchers have made another breakthrough in their development of carbon nanotube technology, packing more than 10,000 working transistors made of the substance onto a single chip.

It is now a decade since IBM first announced a process for fabricating carbon nanotubes in a way that could make them usable for processors. Although silicon has allowed the industry to keep making transistors smaller and smaller, it does not work properly at the nanoscale. Another substance will have to take over for the really tiny processors of the future.

Such processors will be needed to make computing devices and sensors smaller and more energy-efficient.

Ultimately, more than a billion transistors based on carbon nanotubes will need to fit onto one chip, if the substance is to prove its worth. However, IBM's latest breakthrough marks a significant step — previously, no-one had got more than a few hundred of the transistors onto one chip at a time.

"Carbon nanotubes, borne out of chemistry, have largely been laboratory curiosities as far as microelectronic applications are concerned. We are attempting the first steps towards a technology by fabricating carbon nanotube transistors within a conventional wafer fabrication infrastructure," IBM Research physical sciences chief Supratik Guha said in a statement on Sunday.

"The motivation to work on carbon nanotube transistors is that at extremely small nanoscale dimensions, they outperform transistors made from any other material. However, there are challenges to address such as ultra-high purity of the carbon nanotubes and deliberate placement at the nanoscale. We have been making significant strides in both."

IBM's last big breakthrough in the field of carbon nanotubes came just under a year ago, when the firm said it had managed to make a well-performing carbon nanotube transistor with sub-10nm channel lengths — this is the sort of scale where silicon is no longer viable.

Carbon nanotubes are, as their name suggests, atom-thick sheets of carbon rolled into tubes. Graphene , another nanoscale carbon substance, is also in the running for taking over from silicon, as is the graphene-like two-dimensional form of molybdenum disulphide .