Start with the fact that digital computers run on transistors; transistors are key. Next, consider graphene, the nanotechnology cousin of graphite, a versatile material that has hit the news many times in the past several years. Finally, with regard to transistors and computers, graphene has already been dubbed the ‘successor to silicon’; now it looks like that may actually happen. IBM Watson Research Center (New York, USA) has announced an industrial process to produce graphene transistors that run at 100 GHz, or about ten times the speed of silicon.
That’s not a trivial increase, 10:1, but the most important words here are ‘industrial process.’ The ‘trick’ with any new material, nanotech or not, is whether it can be produced in the quantities and purities necessary for commercial markets. In the laboratory, IBM has developed a new procedure for making the graphene in epitaxial layers. This is a removal process, that starts with a 2.5 inch wafer of silicon carbide, heated until the silicon evaporates leaving a one atom thick layer of graphene, in a sense, ‘grown’ on wafers. It’s a process much like those currently used to produce silicon wafers, meaning that the graphene process should be readily adaptable to existing equipment and know-how.
Perhaps the most important development in the IBM announcement isn’t so much the graphene wafers, but the addition of better insulation to the wafer. Graphene is easily affected by its environment, especially electromagnetic interference, so finding an efficient insulator – a thin polymer layer between the graphene layer and the dielectric layer – was a factor in raising the operating speeds of the graphene transistors.
Walter de Heer, a professor of physics at Georgia Tech in Atlanta who pioneered methods used to work with epitaxial graphene, says the IBM device is a milestone because of its speed and because it was made using practical fabrication techniques. “This is not pie-in-the-sky stuff, this is real,” he says. “This development is really going to turn into a communications device not too long from now.”
De Heer notes that the IBM devices don’t yet realize graphene’s full potential. By carefully controlling the growing conditions, his group 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.
[Source: Technology Review]
It’s not time to invest in graphene stocks (stock in bins or the paper kind), but the laboratory work shows that commercial application is only a few years away. Since this development is IBM, working in part, at the behest of the U.S. Defense Department, it’s a reasonable bet that this announcement signals a real chance for graphene to become one of, if not the major material to replace silicon in transistors.