Carbon nanotube transistors of the future

Moore’s Law has become an endangered species. No longer is it a safe assumption that the number of transistors in processors doubles every two years. Intel abandoned this expectation at the ISC 2016 Conference in Frankfurt, Germany. Processor performance barely increases even though they become more energy efficient, and the growth of transistor density has slowed down remarkably. Since considerable time, the industry is also looking for alternatives to silicon as physical limits to its useful further miniaturization are approaching.

Enter carbon nanotubes. The University of Wisconsin at Madison has reached a major milestone in manufacturing transistors out of carbon nanotubes that leave its silicon cousins way behind in terms of conductivity. An increase of 90% in current was measured by pitting a 140 nm carbon nanotube transistor against a 90 nm silicon P-channel MOSFET transistor. The carbon nanotube FET did well even under the disadvantage of a larger node, but the jury is still out on a comparison to current 14 nm FinFET or Tri-Gate transistors.

Carbon nanotubes consist of rolled single-atom layers. They are among the most highly conductive materials known to man. Carbon-based transistors might support a five-fold increase of performance compared to silicon while energy consumption will decrease to one-fifth of present levels.  But manufacturing had always run into problems with minuscule metal contaminations that massively affected conduct of electricity, and thus performance. New technology developed at UW Madison resolved that by filtering impurities with the assistance of a polymer that leaves 99.99 percent pure carbon layers.

This permitted a new production process that places carbon nanotube transistors on a 1x1 inch wafer. But to render the technology interesting and affordable for commercial use, this process needs to become scalable to produce larger wafers and higher transistor densities. First experiments appear to have been successful. Still, several years will likely pass before carbon nanotubes will appear in commercially available processors, since chip manufacturers will also need to invest heavily in adjusting their manufacturing processes and factories.

RAM might take this leap a lot sooner. Fujitsu is already working on commercialization of nano-RAM (NRAM) based on carbon nanotubes and plans to initiate mass production based on licensed technology of Nantero, the world leader in carbon nanotube electronics, by 2018.

Along the concept, if not the formula, of Moore’s Law, somewhere between 20-50 years out, further miniaturization of IT elements and devices (but also their transition and fusion into biotechnology and transhumanism) will be dominated by a transition from software into hardware, a confusion of the two so complete that it will literally become impossible to know where the boundary between them ought to be drawn. And that is precisely the point: perhaps there shouldn’t be a boundary, especially if the next step or, rather, quantum leap, as some conjecture, should be DNA computing.

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