June 25, 2001
IBM Research Team Develops
World's Fastest Silicon Transistor
Chip Runs at 210 Gigahertz, Promises
To Hold Down Cost of High-Speed Devices
By WILLIAM M. BULKELEY
Staff Reporter of THE WALL STREET JOURNAL
International Business Machines Corp. scientists said they have developed
the world's fastest silicon transistor, a development that promises to hold
down the costs of high-speed communications devices.
IBM said it has built a transistor that runs at 210 gigahertz, which is twice
as fast as current communications chips and more than 100 times faster
than the Pentium 4, the Intel Corp. microprocessor that powers
state-of-the-art personal computers.
The fact that the transistor is made of silicon
rather than expensive and exotic materials
such as gallium arsenide or indium phosphide
means that high-speed communications chips
can be made with cheap material on existing
equipment.
"It's a little, tiny chip, but it creates a gigantic
step as far as technological advancement," said Frank Dzubeck, a
Washington-based telecommunications analyst. He said such performance
could ultimately result in wireless phones that could handle enough
bandwidth to deliver video.
IBM achieved the high speed by depositing a 200-atom-thick layer of
silicon germanium atop the basic silicon chip and redesigning the vertical
bipolar transistor to make it more efficient, said Bernard Meyerson, the
IBM scientist who discovered in 1989 that silicon germanium could speed
chip performance.
IBM has been touting silicon germanium, known as SiGe (rhymes with
Ziggy) for almost a decade, but most outsiders predicted it could never run
fast enough for future high-speed needs. But Mr. Meyerson said "it will
probably go north of 300 gigahertz. This is a space in which we never
thought we'd play."
IBM has a long history of building sophisticated chips for its own use, but
in 1995 it started selling its expertise to outside companies. It is now the
biggest producer of chips called application-specific integrated circuits,
designed by customers with IBM's help and then built by IBM. Many of its
biggest customers are makers of communications equipment, including
Alcatel SA, Nortel Networks Corp. and Cisco Systems Inc.
While other companies have started to promote SiGe technology, IBM has
been developing it since 1989 and "clearly" has "the most manufacturable
and repeatable process," said Paul Cunningham, director of business
development for Sierra Monolithics Inc. a Redondo Beach, Calif.,
company that designs circuits for high-speed optical switches. "I don't think
anyone else is close to 210 gigahertz. We're pretty excited," he said.
Mr. Meyerson of IBM said very high-speed communications chips made
of silicon mean that wireless technology could bring huge amounts of data
into the home. That would avoid having to lay fiber cables to homes.
In other cases, he said, customers will use the SiGe technology at much
lower speeds because it needs far less power, avoiding the heat buildup
that is increasingly affecting communications systems.
Mr. Meyerson said one of the most significant impacts of the new
development is that chip designers will be able to get improved
performance even when they can no longer make ever-thinner lines on the
silicon chips. "People argue about when it will happen, but as a physicist I
know there are physical limits." Moreover, the bipolar SiGe transistors can
be easily integrated onto a logic chip, such as a microprocessor, unlike
other materials. |
