Nanotech Memory Chips Might Soon Be a Reality
June 7, 2004
By BARNABY J. FEDER
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,
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
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.