Researchers at the University of California, Riverside and at the University of Manchester in the United Kingdom have discovered that adding a layer of one-atom-thick graphene material on each side of a copper film increased heat-conducting properties up to 24 percent.
“This enhancement of copper’s ability to conduct heat could become important in the development of hybrid copper-graphene interconnects for electronic chips that continue to get smaller and smaller,” said Alexander Balandin, EE professor at the Bourns College of Engineering of UC Riverside. Copper is used for most semiconductor interconnects, and the increasing number of transistors in chips has put an enormous strain on copper’s interconnect performance. With little room for further improvement, there is a strong motivation to develop hybrid interconnect structures that can better conduct electrical current and heat.
The experiments conducted by Balandin and his fellow researchers showed significant improvement in the thermal properties of graphene-coated copper films despite the graphene’s thickness of only one atom. The researchers found the improvement is the result of changes in copper’s nano- and microstructure, not from graphene’s action as an additional heat-conducting channel.
Examining grain sizes in copper before and after adding graphene showed chemical vapor deposition of graphene conducted at high temperature stimulates grain size growth in copper films, which results in better heat conduction. Additionally, the researchers found that heat conduction improvement by adding graphene was more pronounced in thinner copper films.
The enhancement should further improve as future copper interconnects scale down to the nanometer range from today’s micrometers. Balandin and fellow researcher Konstantin S. Novoselov, professor of physics at the University of Manchester, are corresponding authors for the paper in the journal Nano Letters.
Balandin and fellow researcher Konstantin S. Novoselov, professor of physics at the University of Manchester, are corresponding authors for the paper in the journal ). In 2010 Novoselov shared the Nobel Prize in Physics with Andre Geim for their discovery of grapheme.
In 2010 Novoselov shared the Nobel Prize in Physics with Andre Geim for their discovery of graphene. Last year, Balandin was awarded the MRS Medal from the Materials Research Society for discovery of unusual heat conduction properties of graphene. The National Science Foundation and Semiconductor Research Corporation supported the research work at UC Riverside.