iPods, Chicken Wire and the Future of Memory

It seems that every few months, companies come up with ways to cram more
memory into flash drives -- the memory technology that makes things like iPods
tick. In a few years, however, flash drive memory development as we know it will
hit a brick wall and new techniques will be needed to increase capacity. That's
where graphene comes in.

Many consumers take it for granted that the next generation of iPod, cell phone or flash drive will contain ever more memory to store music, photos and videos.
That's because scientists and engineers have continually devised ways to shrink the components on flash memory chips to cram more data into small devices.
But eventually -- within a couple of years, perhaps, and almost certainly within a decade -- flash memory will run into fundamental limits on how small its circuitry can be built.

That has led a number of research groups and companies to begin searching for alternatives.

Very Thin, Very Tough
Jim Tour leads one of these groups in Houston. But the Rice University chemist said he and his laboratory didn't set out to tackle the memory problem when they began working with graphene.

A single layer of graphite, which is used in the common pencil, graphene is composed of carbon atoms and looks like tiny chicken wire. In this configuration, it is an exceptionally strong material that efficiently conducts electricity.

While working with graphene in his lab, Tour realized that bits of it could be designed to store a charge, the underlying basis of memory.

As he began testing graphene as a memory device, Tour found that it worked better than silicon-based flash memory in a number of respects: It leaked less current, it generated very little heat and it operated in temperatures from minus 100 degrees Fahrenheit to nearly 400 degrees.

'A Long Way to Go'
Its circuitry can also be built at much smaller sizes -- less than 10 nanometers compared with the current 34-nanometer circuitry of the smallest flash memory devices. And perhaps most importantly, graphene memory can be stacked in three dimensions rather than arrayed in two, allowing for considerably more memory to be crammed into a single chip.
Tour said his lab is working with industry to determine if graphene-based memory can be commercialized.

"There's a long way to go, and it will take quite a bit of money to bring this technology along," Tour said. "But it does have some advantages over today's flash memory."

Understanding Graphene
An expert in the computer memory industry said it will be difficult to develop a graphene memory device, because flash memory and so many other chips are based on silicon.
"We just don't understand these other materials nearly as well as silicon," said Jim Handy, a semiconductor analyst with the Los Gatos, Calif.-based firm Objective Analysis.
Since silicon's first use in electronics half a century ago, billions of dollars have been spent to research and develop silicon-based materials for computer applications, Handy said. That means companies are familiar and comfortable with working with silicon.

Tour says his graphene technology can be deposited on a silicon chip, which may allay some of industry's concerns.