starship-design: Any David Weber readers out there? Molycircs are coming...

["L. Parker" <lparker@cacaphony.net>]

IBM research may mean tiny computer chips
August 27, 2001 Posted: 12:03 PM EDT (1603 GMT)

NEW YORK (Reuters) -- Reaching a long-sought goal in computing research,
scientists have created a computer circuit based on a single molecule, which
could lead one day to far smaller and faster computer chips that use less
power.

International Business Machines Corp. said Monday that its researchers have
built a logic circuit -- a set of electronic components that performs a
processing function -- based on a tiny cylindrical structure made up of
carbon atoms that is about 100,000 times thinner than a human hair.

The breakthrough is IBM's second this year using the molecules called carbon
nanotubes as semiconductors, making them an increasingly viable alternative
to silicon, which forms the base of current chips, IBM said.

"Carbon nanotubes are now the top candidate to replace silicon when current
chip features just can't be made any smaller," said IBM's Phaedon Avouris,
lead scientist on the project. "Such beyond-silicon nanotube electronics may
then lead to unimagined progress in computing miniaturization and power."

Scientists are looking for a replacement for silicon because in the next 10
to 15 years they expect that it will no longer be possible to reduce the
size of chips using silicon, which will limit improvements in chip size and
speed.

Since Intel Corp. introduced its "386" microprocessor in 1985, computer
chips have made exponential advances in both speed and size, increasing the
number of transistors on a chip more than 152 times.

That's what's behind Moore's law, named after Intel founder Gordon Moore,
who predicted in 1965 that the number of transistors, or electronic
switches, on a chip would double every 18 months.

Avouris wasn't able to quantify how chips built of nanotubes would compare
in speed with current silicon ones, but nanotubes are expected to at least
match the improvements Moore's Law dictates for today's silicon chip.

In a couple of years, IBM expects to start working on ways of building the
new chips and will know how the size of the elements in the nanotube chip
compare with those of silicon chips.

Circuits that compute
While researchers had already found a way to form nanotubes into
transistors, IBM's latest achievement showed that a nanotube can be used to
make a logic circuit, the key to computing.

A carbon nanotube is a single molecule that's about 500 times narrower than
the silicon used in today's processor and is about 10 atoms across. In
addition, a nanotube creates less heat than silicon and uses less power and
space.

IBM scientists used a nanotube to make a 'NOT' gate, which has both a
positive and negative transistor, meaning that the entire circuit can
perform the processing functions critical to computing.

A NOT gate is essentially an open or closed switch that changes a '1' to a
'0' and a '0' to a '1'. Previously, nanotube transistors were only positive
and didn't process information.

The next step
IBM said a nanotube circuit's signal output is strong enough to drive other
gates or circuits, which means that more complex circuits could be built
using a single nanotube. These complex circuits are the next step toward
molecular computer chips, IBM said.

The discovery comes about four months after the IBM team said it had built
the first array of transistors out of carbon nanotubes. Prior to that,
nanotubes had to be positioned one at a time or by random chance. That
achievement was a step toward eventual mass production of computer chips.

Scientists have turned to carbon nanotubes because they are the strongest
fiber in nature -- 10 times stronger than steel. They also take advantage of
the very strong bond between carbon atoms -- the same bond that makes
diamonds so hard.

But carbon nanotubes aren't the only contender to replace silicon. Some
scientists, including those at IBM, are studying the possibility of
so-called quantum computing based on atoms.

IBM hopes to begin to develop the carbon nanotubes in two years, although it
will be another 10 to 15 years before a product hits the market.

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