Graphene gets a reality check
One of the world’s leading graphene researchers believes that the material has failed to make its case as the next generation replacement for silicon and will continue to do so.
Prof. Andrea Ferrari, professor of Nanotechnology at the University of Cambridge and also director of its Graphene Centre, told the 2013 International Electron Devices Meeting that the material’s future in electronics will instead lie in “complementary” applications.
Ferrari identified four main drawbacks to graphene’s progress.
- “The lack of a bandgap.”
- “The tendency for scaling to diminish graphene’s inherent advantages. The gate oxide thickness must be more aggressively scaled than gate length and supply voltage, breaking conventional scaling laws.”
- “Complementary logic is realized through electrostatic doping which imposes limits on supply voltages in graphene logic gates.”
- “The low extrinsic mobility of graphene (compared to its intrinsic mobility which is much larger than Si and InP) is a consequence of a large contact resistance (here 2.1 kΩ·μm) and scattering from charged impurities in the top and back oxide. Scattering must be reduced if graphene is to replace InP.”
These problems can be overcome – and even for some of graphene’s likely complementary uses will need to be. But the cost of doing so and the likelihood that graphene will offer similar performance to silicon do not position it as a replacement.
Instead, Ferrari argued that graphene will be used as a material integrated within CMOS-based systems for functions other than transistors, with a few notable exceptions. These, he said, could include such applications as flexible OLED displays and very low-cost devices for food packaging and inventory management.
“You can write a lot of nice papers,” Ferrari said, “but at the moment it has major limitations. I don’t see much use of graphene for conventional electronics.”
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