Nanotech Memory Chips Might Soon Be a Reality

June 7, 2004


Nantero, a start-up developing memory chips using nanotechnology, and LSI Logic, a leading maker of specialty microchips, are expected to announce today that they have transferred Nantero's technology to a standard semiconductor production line.

Nantero is creating NRAM, a high-density nonvolatile random access memory chip, which it hopes will replace existing forms of memory. Its technology, using cylindrical molecules of carbon known as nanotubes, will be used on a production line in LSI's semiconductor factory in Gresham, Ore.

Carbon nanotubes are among the new forms of carbon, known as fullerenes, whose discovery helped ignite interest in manipulation of materials at the molecular level, the field known as nanotechnology. Fullerenes consist of carbon atoms arranged in patterns resembling the nodes of the geodesic domes designed by Buckminster Fuller. Nanotubes, which researchers first created in 1991, consist of single- or multiwalled cylinders that can be less than 10 nanometers wide. A nanometer is one-billionth of a meter.

The transition from laboratory to production line took more than nine months, the companies said, adding that considerable work remains to improve the chips.

"But it's following the same type of road map as any other semiconductor product," said Norman L. Armour, vice president and general manager of the LSI factory in Gresham. Mr. Armour said that processors embedded with carbon nanotube memories in place of static random access memory, or SRAM, could be supplied commercially from the factory's pilot line next year if no problems developed.

If so, analysts said, such devices could emerge as one of the first products to exploit something other than the extraordinary strength of carbon nanotubes.

The nanotubes are up to 100 times as strong as steel and one-sixth its weight, qualities that have quickly led to their use in products like tennis rackets and automotive plastics, where they are mixed with other materials to improve their performance.

Researchers have also shown that the nanotubes have extraordinary electrical and magnetic characteristics. Recent reports, for example, have highlighted their ability to be quickly altered from metal-like conductors into semiconductors and back by applying magnetic fields.

Such novel qualities have helped make them a powerful symbol of nanotechnology's potential, but except as strengtheners nanotubes have proved difficult to bring to market. The challenges have included preventing clumping and the tendency of the simplest manufacturing approaches to produce mixes of single-walled and multiwalled tubes with varying characteristics.

Nantero's design applies charges to groups of single-walled nanotubes suspended over an electrode. Applying opposite charges to the tubes and the electrode causes the tubes to bend down, creating a junction that represents a 1. Applying like charges forces them apart into the 0 state. As with all digital memory, NRAM stores data as a pattern of 1's and 0's.

Carbon nanotube memories could sharply improve the performance of cellphones, laptop computers and other electronic devices. Like today's flash and SRAM memories, carbon nanotube designs can maintain data when power is turned off, an advantage over dynamic random access memory, or DRAM, memory chips, which must constantly be refreshed. But it can operate considerably faster and on less power than flash memory, and is much cheaper and more compact than SRAM.

Analysts caution that Nantero's carbon nanotubes face plenty of competition. Memories that hold their charge are crucial to improving the performance and design flexibility of a wide range of electronic products, and thus have become the most profitable and fastest-growing segment of the $35 billion memory market, according to Radu Andrei, a Web-Feet Research analyst based in Dallas. That is attracting heavy investment in technologies that could replace flash and SRAM.

"I count around 30 technology variations trying to get a piece of that pie," Mr. Andrei said. Among them are I.B.M., Intel, Motorola and numerous start-ups. Flash memory is now so inexpensive, he added, that innovators will have a hard time displacing it from all but the most demanding applications even if they surpass it technically.