Swinging nanotubes point way to next-generation RAM
The first 10Gb nanotechnology memory (NRAM) device has been built in the laboratories of Nantero, the Boston, Massachusetts-based company has said.
Using carbon nanotubes a billionth of a metre in diameter sprinkled onto a silicon wafer, the device has been made using mostly standard chip production techniques. The company claims that the technology can combine the speed and price of dynamic memory with the non-volatility of flash, making it a strong candidate for the eagerly awaited universal memory devices that the industry hopes will replace all other types.
If commercialised at a suitable price, it could replace DRAM, flash memory and hard disks in a wide variety of digital devices including PCs, phones and MP3 players.
NRAM works by balancing the nanotubes on ridges of silicon. Under differing electrical charges, the tubes can be physically swung into one of two positions representing one and zero. Because the tubes are so small -- under a thousand atoms -- this movement is very fast and needs very little power, and because the tubes are a thousand times as conductive as copper it is very easy to sense their position to read back the data.
Once in position, the tubes stay there until a signal resets them: with a tensile strength twenty times that of steel, they are expected to survive around a trillion write cycles.
"We are thrilled with these developments", said co-founder and chief executive Greg Schmergel in a statement. "When we announced that we intended to make a universal memory chip using carbon nanotubes (NRAM), the primary concern held by most observers was that carbon nanotubes grow indiscriminately and it's extremely difficult to align them. Creating this enormous array of suspended nanotubes using standard semiconductor processes brings us much closer to our end goal of mass-producing NRAM chips."
The company said that it solved the alignment problem by processing the wafer after the tubes were applied, using lithography and etching to remove the out of position components, and having a great deal of on-chip redundancy.
One of the rules of the development, said Schmergel, was that no non-standard equipment was to be used. The company plans to licence its techniques to other chip companies, and says that it can see a $100bn (£61bn) market for its memories.
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