AIM (Apple, IBM, Motorola) Alliance member IBM has developed a transistor technology that permits smaller, faster, less energy-hungry silicon semiconductors than those currently produced.
The discovery enables more transistors to be placed on these chips, and is said by some analysts to support Moore's Law – formulated by Intel co-founder Gordon Moore. The law states that the number of transistors that can be placed on a computer chip will double every 18 months. Prevalent wisdom is that the law will hold true for at least ten more years – but observers point to the physical-size limitations of transistors built using silicon limiting the number of transistors that can be placed on a chip.
But IBM researchers have now built the world's first array of transistors out of carbon nanotubes –cylinders of carbon atoms that measure as small as 10 atoms across, and that are 500 times smaller than silicon-based transistors. IBM built these using a batch process for forming large numbers of nanotube transistors. The smaller size of carbon nanotube semiconductors allows more transistors to be placed on a chip than is possible using silicon.
Carbon the key Previously, nanotubes had to be positioned one at a time, or by random chance, which, though feasible for scientific experiments, is considered impractical for mass production, IBM said. The batch process, called "constructive deconstruction", overcomes a major obstacle in the production of carbon nanotubes, which can be either metallic or semiconducting, the company said.
Previously, researchers had been unable to use carbon nanotubes as transistors because existing synthetic methods of production yield a mixture of metallic and semiconducting nanotubes that stick together to form ropes or bundles. This compromises the usefulness of nanotubes, because only semiconducting nanotubes can be used as transistors.
Given this challenge, the obstacle to using semiconducting nanotubes has been the lack of a method of separating the metallic and semiconducting nanotubes on a scale suitable for mass production, said IBM. The constructive destruction technique achieves this by allowing scientists to produce semiconducting carbon nanotubes with the electrical properties required to build computer chips, by destroying metallic nanotubes using an electric shockwave. This leaves only the semiconducting nanotubes needed to build transistors.
If applied to the manufacture of non-embedded chips, the discovery could lead to an impressive advance in the potential maximum-speeds of the microprocessors used in personal computers, including Macs.