Nanotube Electronics Could Replace Silicon – IBM Research Breakthrough

IBM announced a major engineering breakthrough that could open the way to replacing silicon transistors with carbon nanotubes in future electronics and computing technologies.

Silicon transistors have become dramatically smaller in the last decades following Moore’s Law – the observation that the number of transistors per unit area doubles every two tears. However, silicon transistor technology is approaching a point of physical limitation.

With Moore’s Law running out of steam, shrinking the size of transistors – including the channels and contacts – without compromising performance is a research and manufacturing challenge. Carbon nanotube technology could lead to much smaller transistors and keep electronics and computing devices on the Moore’s Law of exponentially decreasing size and thus increasing performance. However, as devices become smaller, increased contact resistance for carbon nanotubes has hindered performance gains until now.

Nanotube Electronics Could Be Operational Sooner Than Expected

IBM Nanotube ContactIBM’s new contact approach overcomes a hurdle in incorporating carbon nanotubes into semiconductor devices, which could result in smaller chips with greater performance and lower power consumption. The breakthrough could overcome contact resistance challenges all the way to the 1.8 nanometer node – four technology generations away.

The research results, published in Science with the title “End-bonded contacts for carbon nanotube transistors with low, size-independent resistance,” could lead to dramatically faster, smaller and more powerful computer chips beyond the capabilities of traditional semiconductors.

Semiconducting Single-Walled Carbon Nanotubes (SWNT) have potential size and conductivity advantages over silicon for making smaller transistors. However, as metal electrical contacts decrease in size, the associated resistance increases to impractical values. The researchers built a high-performance SWNT transistor with a sub–10-nanometer contact length, by reacting molybdenum films with semiconducting carbon nanotubes. The resistance of the contacts remained low even at 10-nanometer scale.

“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 & Technology at IBM Research. “As silicon technology nears its physical limits, new materials, devices and circuit architectures must be ready to deliver the advanced technologies that will be required by the Cognitive Computing era. This breakthrough shows that computer chips made of carbon nanotubes will be able to power systems of the future sooner than the industry expected.”

This brings us a step closer to the goal of a carbon nanotube technology within the decade.

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. Today’s top-of-the-line silicon chips have 14-nanometer features. The IBM research result show that that contacts less than 10 nanometers long don’t compromise performance, and could be extended down to 1.8 nanometer.

The new result from IBM represents a “fantastic strategy” for addressing the contact problem, said Michael Arnold, a professor of materials science and engineering at the University of Wisconsin, who was not involved in the research.

Images from IBM Research.

Giulio Prisco is a freelance writer specialized in science, technology, business and future studies.