Silicon has been the foundation of modern computers since they were first invented over 70 years ago. However, it's reaching its upper physical limit and performance threshold, as modern electronics continues moving towards the atomic scale in order to decrease the distance between integrated circuits and increase computer performance. Now, IBM researchers have created the first integrated circuit composed of the 'wonder material' graphene.
Graphene was discovered in 2004 by Russian-born scientists Andre Geim and Konstantin Novoselov in 2004. It comes from the lead of a pencil, is one atom thick and has a honeycomb structure akin to chicken wire that conducts electricity 100 times faster than silicon. Yu-Ming, an IBM research scientist told iSGTW. "It's ideal for high-speed electronics and for achieving ultra-small devices."
The research published in the journal Science, describes how IBM researchers created a wafer-scale graphene integrated circuit. "The development took us about a year to resolve various fabrication and integration issues, such as the adhesion between metal and graphene. This is one of the first versions of working circuits," said Yu-Ming.
This new chip operated at 10GHz and represents an important step in semi-conductor technology. Yu-Ming said, "Commercial products may take from five to 10 years, depending on complexity of the products."
Could this be a precursor to future microprocessor technology? While this is the first integrated circuit based on graphene, it is not intended to be used in computers. The circuit itself is designed for wireless communications. However, "It would be challenging to replace silicon for digital logic applications. Further research in graphene may be able to provide a solution to this deficiency," said Yu-Ming.
Creating this circuit was no trivial task as the researchers had to address issues such as contact resistance, graphene integration with inductors and preservation of graphene quality during processes to make the circuit work properly.
In terms of performance, the highest frequency demonstrated by a silicon transistor is 300GHz, which is comparable to the highest values seen in graphene transistors thus far. "However, for the same device dimension, graphene transistors exhibit a higher frequency than that of silicon, and therefore, graphene has the advantage in scaling over silicon. Currently, we do not see any major bottlenecks or fundamental limitations for graphene transistors," said Yu-Ming.
