Graphene ribbons to replace copper on chips?

Not content with taking on the might of silicon, now graphene in all its two-dimensional glory is giving the evil eye to copper. According to an announcement from Rensselaer Polytechnic Institute, graphene is a promising candidate to replace copper as the size of circuitry on chips shrinks ever smaller.

The interconnects on silicon chips – the pathways which conduct electricity around the circuits – are made from copper. But as chips get smaller, heat high power consumption, and even permanent failure become more and more of an issue.

Now the scientists, who have been working with models on supercomputers, think layered graphene nanoribbons could be a good candidate to replace the copper interconnects.

"Graphene shows enormous potential for use in interconnects, and stacking up graphene shows a viable way to mass produce these structures," said Professor Saroj Nayak of Rensselaer’s Department of Physics, Applied Physics, and Astronomy.

He explains that when cut into nanoribbons, graphene does exhibit a bandgap – something it doesn’t have when it in sheets, and something that is undesireable in interconnects. However, the bandgap can be reduced by layering the ribbons, up to four to six layers thick. It is possible to add more layers of course, but it doesn’t reduce the band gap.

"Copper’s limitations are apparent; as increasingly smaller copper interconnects suffer from sluggish electron flows that results in hotter, less reliable devices. Our new study makes a case for the possibility that stacks of graphene ribbons could have what it takes to be used as interconnects in integrated circuits," Prof. Nayak concludes.

The press release is here, and the ACS Nano paper, "Effect of Layer Stacking on the Electronic Structure of Graphene Nanoribbons." Is here.