In 2015 — now just over a year away — the International Technology Roadmap for Semiconductors (ITRS), which is set out by the industry’s top experts, predicts that the copper wiring that connects together the billions of transistors in a modern CPU or GPU just can’t be miniaturized any further. The copper wires can only get so thin before the increased resistance and other manufacturing issues make them unworkable. Graphene, however, by virtue of its status as a wonder material, isn’t hindered by the same puny restrictions as copper and could theoretically scale down to just a handful of nanometers or less, allowing for the creation of computer chips that are orders of magnitude more dense and powerful, while consuming less energy.

Way back in 2011, IBM built what it called the first graphene integrated circuit, but in actuality it was more like a graphene field effect transistor (FET) and inductor connected together with other standard, CMOS components, such as plain ol’ copper wires. Now a team at the University of California, Santa Barbara (UCSB) have proposed the first all-graphene chip, where the transistors and interconnects are monolithically patterned on a single sheet of graphene.

In a research paper, titled “Proposal for all-graphene monolithic logic circuits,” the UCSB researchers say that “devices and interconnects can be built using the ‘same starting material’ — graphene,” and, perhaps more excitingly, “all-graphene circuits can surpass the static performances of the 22nm complementary metal-oxide-semiconductor devices.” To build an all-graphene IC (pictured above), the researchers propose using one of graphene’s interesting qualities, that depending on its thickness it behaves in different ways. Narrow ribbons of graphene are semiconducting, ideal for making transistors — while wider ribbons are metallic, ideal for gates and interconnects.

For now, UCSB’s design is just that — a computer model that should technically work, but which hasn’t been built yet. In theory, though, with the worldwide efforts to improve high-quality graphene production and patterning, we should be able to build an all-graphene IC in the next few years. Even then, though, it will still take a long time to go from laboratory prototype to full-scale commercial production — perhaps a decade or more. For the time being, the higher electron mobility of III-V semiconductors compared to silicon should provide a stopgap solution for the continuing miniaturization and ultra-low-power requirements of modern computing. When graphene ICs do finally take off, though, we have terahertz switching speeds and transistor densities in the tens-of-billions to look forward to.

Now read: The wonderful world of graphene and other wonder materials

Research paper: dx.doi.org/10.1063/1.4818462 – “Proposal for all-graphene monolithic logic circuits”