IBM Microelectronics is hitting the road with its new spin on
silicon for making faster computer chips.
The IBM chipmaking division is working to popularize its relatively new
silicon-on-insulator (SOI) chipmaking technology, both through licensing and
manufacturing agreements as well as by using it in its own chips.
Wide adoption of SOI technology, used to increase performance or lower
the power consumption of a processor, would be a point of pride for IBM as
it would prove detractors of the technology wrong. At the same time,
licensing fees and contract manufacturing would help boost IBM
Microeleclronics' bottom line.
To date, IBM Microelectronics has only one public SOI licensee, a joint
venture between IBM, Sony and Toshiba, that will create Cell, a new Internet access chip.
But executives say the company has others waiting in the wings.
One SOI adopter could be Advanced Micro Devices. An AMD spokesman confirmed
that IBM and AMD entered into an agreement for IBM to provide design
assistance with forthcoming AMD chips that will use SOI.
IBM has also been hired to manufacture Alpha processors for Compaq
Computer and PA RISC chips for Hewlett-Packard, both using its SOI
technology.
The company has already shipped high-end p680 Unix servers containing
PowerPC chips using SOI. A company spokesman said IBM will begin releasing
SOI over its remaining PowerPC, SRAM and custom ASIC product lines, starting
in the third quarter of this year.
The SOI chipmaking method places an insulator between the
transistor and the bed of silicon upon which it rests. The insulator helps
reduce the amount of electrical energy absorbed from the transistor, making
for a stronger signal between transistors.
When compared to a similar chip at the same clock speed, an SOI equipped
chip can offer either increased performance or reduced power consumption.
IBM says the method can boost performance by up to 30
percent or cut power consumption by more than half.
Because of its properties, IBM sees SOI as having particular benefits for
chips used in servers and low-power handheld computers.
"We're getting a lot of demands from a lot of sides, including dense server
configurations," said Bijan Davari, vice president of
technology and emerging products for IBM Microelectronics. "Anywhere you
have significant power constraints or the need for performance and battery
life, SOI is becoming very attractive."
Low-power chipmaker Transmeta would be another obvious target for SOI.
"Transmeta, we have talked to them...and there are other server
companies that are using our SOI for high performance applications," Davari
said, declining to offer further details.
If there's a downside to SOI, it's the costs of the process. IBM says its
method, which uses a layer of oxide between the transistor
and silicon substrate, adds only about 10 percent to the cost of a finished
wafer, before it is divided into individual chips.
"If you consider the cost of cooling technology, then SOI more than
compensates," Davari said.
But for chipmakers dealing with already thin profit margins, even a modest
increase in cost may be prohibitive against using SOI in high-volume chip
manufacturing, such as mainstream desktop PC processors, analysts say.
"No doubt about it, take any bulk silicon-based circuit and convert it to
SOI and there will be a performance gain," wrote Dan Hutcheson, president of
LSI research, in a series of reports on SOI technology. "The real issues lie
in whether the performance benefits are enough to outweigh the design
hassles and the additional cost. This question can only be answered by
first looking at the manufacturing prowess of the companies involved as well
as the markets they engage in."
Intel says SOI is still too expensive. A spokesman argued that even a small
amount of extra cost, multiplied by the 100 million or so chips Intel produces
per year, makes SOI's cost prohibitive.
Intel has conducted research into SOI, and "what we came up with is that
there is some performance increase," spokesman Manny Vara said.
"The issue we have is that it adds complexity and cost. Therefore, for us,
it makes no sense...because any performance increases would be negated by
the added cost and complexity."
Analysts say it's unlikely SOI will show up in mainstream processors any
time soon.
Hutcheson noted that IBM focuses on low-volume, high-performance custom
chips, while Intel pumps out mainstream microprocessors by the bucket. "Thus,
SOI makes much more sense for IBM than it does for Intel today," Hutcheson
said in his SOI report.
"This is why (Intel) never implements a technology until it is ready for
prime time," he wrote. "If and when SOI makes sense in volume manufacturing,
you can bet Intel will be there.
"The key company to watch for in this transition is AMD," he continued.
"They are also a high-volume manufacturer; they don't have to implement
across multiple (factories) and they are particularly good at wringing the
most out of new technologies."
AMD has announced that SOI will be incorporated in its Hammer family of
processors, starting with the desktop-oriented ClawHammer, which will
replace the current Athlon. AMD plans to provide ClawHammer
samples to PC makers late this year. The company plans to ship it
in volume in the first quarter of 2002.
Motorola is also targeting SOI for its next-generation G4 chip, code-named
Apollo.