PORTLAND, Ore.Pure carbon interconnects, cast as tiny ribbons of graphene, will outperform copper interconnects below 30 nanometer line widths, according to researchers at the Georgia Institute of Technology (Georgia Tech).
Besides lower resistivity, the researchers also claimed that graphene interconnects enjoy high electron mobility, better thermal conductivity, higher mechanical strength and reduced capacitive coupling between adjacent lines.
The researchers characterized graphene interconnection lines as small as 18 nanometers wide and found that they perform as well or better than even the most optimistic estimates of how copper interconnects will perform at those sizes. Unlike copper, whose resistivity goes up at these fine line sizes due to scattering at grain boundaries and side wallsgraphene's conductivity is enhanced by quantum effects at nanoscale sizes.
The researchers cut their ribbon from a block of pure graphite, but claim their results apply to graphene films as well. Flakes were removed from the block and tested on an insulating substrate using electron beam lithography to form graphene ribbons and to attach electrodes. Nanoribbons of graphene were tested in widths ranging from 18- to 52-nanometers.
Raghunath Murali, a research engineer in Georgia Tech's Microelectronics Research Center, performed the work with fellow researchers Kevin Brenner, Yinxiao Yang, Thomas Beck and James Meindl. Funding was provided by the Interconnect Focus Center, a Semiconductor Research Corporation/DARPA Focus Center, and the Nanoelectronics Research Initiative through the INDEX Center.