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February 04, 2010

IBM Makes Graphene at 30 GHz and Potential of 100 Ghz to 1 Terahertz Graphene

MIT Technology Review - IBM has created prototype graphene transistors made from atom-thick sheets of carbon, operate at 100 gigahertz--meaning they can switch on and off 100 billion times each second, about 10 times as fast as the speediest silicon transistors.

IBM has created graphene transistors that leave silicon ones in the dust. The prototype devices, made from atom-thick sheets of carbon, operate at 100 gigahertz--meaning they can switch on and off 100 billion times each second, about 10 times as fast as the speediest silicon transistors.

The first applications of graphene transistors will likely be as switches and amplifiers in analog military electronics. But the researchers say it will be years before the company begins commercial development on carbon electronics.

Walter de Heer, a professor of physics at Georgia Tech in Atlanta, by carefully controlling the growing conditions, has made graphene that conducts electrons 10 times faster than the material used by the IBM team. This higher-quality graphene could, in theory, be used to make transistors that reach terahertz speeds, though de Heer says many things could go wrong during scale-up.

Avouris says the IBM team will work to improve its transistors' speed by miniaturizing them. The ones it has made so far are 240 nanometers long, which is relatively large--silicon electronic components are down to about 20 nanometers. Avouris also believes that their performance could be improved by making the insulating layer thinner. "The next step is to try and integrate these transistors into a truly operational circuit," he says.



Arstechnica had coverage.
The graphene FETs in this work were tested up to 30GHz and, extrapolating those results, the authors showed that the FETs would operate, albeit poorly, up to 100GHz. Similarly sized Si devices are limited to 30GHz operation. Assuming these devices can be scaled, they will undoubtedly present a dramatic speed increase over current generation Si.

Science - 100-GHz Transistors from Wafer-Scale Epitaxial Graphene
The high carrier mobility of graphene has been exploited in field-effect transistors that operate at high frequencies. Transistors were fabricated on epitaxial graphene synthesized on the silicon face of a silicon carbide wafer, achieving a cutoff frequency of 100 gigahertz for a gate length of 240 nanometers. The high-frequency performance of these epitaxial graphene transistors exceeds that of state-of-the-art silicon transistors of the same gate length

11 page pdf of supplemental material





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