Issue Date: April 11, 2011
New Route To Graphene Devices
A new strategy for fabricating graphene-based transistors—one that relies on materials and methods compatible with those used in the microelectronics industry—has been developed by researchers at IBM (Nature, DOI: 10.1038/nature09979). The work may lead to commercially viable techniques for manufacturing electronic devices that exploit the unique properties of graphene, a layer of carbon one atom thick.
Graphene’s outstanding electronic and other properties have sparked a wave of research aimed at making circuit components based on the ultrathin material. The goal is to use graphene to make circuit elements that are smaller and that outperform today’s devices.
With that goal in mind, a number of research teams have incorporated graphene electrodes into radio-frequency (RF) transistors, fast-acting signal amplifiers that play a central role in wireless communication systems. But the graphene electrodes in the fastest of those transistors are prepared by a laborious manual procedure.
Graphene can be prepared more efficiently in larger batches via vapor deposition methods. But those procedures generally call for depositing the film on a layer of silicon dioxide, which adversely affects the electronic performance of graphene devices.
To sidestep those limitations, Yanqing Wu, Yu-ming Lin, Phaedon Avouris, and coworkers at IBM’s Thomas J. Watson Research Center developed a vapor deposition method in which graphene ends up on diamond-like carbon, a material well-known to the semiconductor industry with desirable electronic properties. Initial tests show that RF transistors made via the new method operate at very high frequencies and work well even at cryogenic temperatures.
“The approach of the IBM team is very interesting because it is compatible with common semiconductor processing,” says Frank Schwierz, a device physicist at the Technical University of Ilmenau, in Germany. At this early stage, before the fabrication method has been optimized, Schwierz is cautious about calling the technique a breakthrough. “But it may turn out to be very useful in the future,” he says.
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