IBM advances chip speeds

The arcane technology improves a chip's conducting efficiency. IBM's silicon germanium technology embeds germanium atoms in certain locations in the silicon crystal that forms the base of microchips. Infused with germanium, the silicon substrate becomes a better conductor of electricity.

"Infusing a little germanium really speeds up the current," resulting in chips that can operate much faster, said IBM spokesman William O'Leary.

Current chips use a silicon dioxide base that can be enhanced with gallium arsenide molecules. Silicon germanium technology has been under development at several companies for about five years.

The technology is important for cell phones, but also for pagers, personal digital assistants, and global positioning system receivers. All these devices require the radio frequency equipment of the type IBM is offering.

"It's going to have a big effect, but there's going to be a lag time," said Allen Liebovitch, an analyst with International Data Corporation. "Right now it's just IBM that has it. It's going to take a long time to proliferate through the market."

Silicon germanium is one of a number of chip innovations that IBM has announced this year.

In August, the company became the first to commercially ship a processor using copper, rather than less efficient aluminum, wires to conduct electricity. Additionally, IBM introduced a technology called "Silicon-on-Insulator" which is expected to boost chip speeds by insulating transistors better.

In the short run, silicon germanium technology will give IBM a foothold in radio frequency chips, a new market for the high-tech giant, Liebovitch said.

But in the long run, the new technology has potential to revolutionize microprocessors, said William Strauss, president of Forward Concepts.

"Intel is talking about [chips running at speeds of] about 1 gigahertz," Strauss said. Silicon germanium, however, "gets you up into the 50-gigahertz range," more than 100 times faster than Intel's current top-of-the line 450-megahertz chips.

"This is literally a revolutionary increase in speeds," much more significant than IBM's new copper chip technology, Strauss said.

While using silicon germanium in highly complex computer chips is several years away, IBM has a lead of at least nine to 12 months over competitors trying to develop silicon germanium technology, Strauss said.

Silicon germanium's future now hinges on whether the new technology can be integrated into current products at a price the manufacturers are willing to pay, Strauss said. Modifying existing chip manufacturing equipment will be expensive. Manufacturers seeking a boost in conductivity currently infuse gallium arsenide into the silicon layer. Gallium arsenide has been getting cheaper in recent years.

One advantage silicon germanium has over gallium arsenide is it fits into existing current manufacturing processes, which means it can be used on 8-inch silicon chip wafers. Gallium arsenide, on the other hand, is still more of a specialty technology and is only available on 4-inch wafers, which means the cost per chip is higher, Strauss said.

Portable equipment needs to be able to process information very quickly in order to keep pace with the high frequencies of the radio spectrum--frequencies in the range of 1 gigahertz--used by wireless communications devices. Gallium arsenide, while capable of operating at those high speeds, is expensive and hard to tie together with traditional computer chips, O'Leary said.

"It's like cooking two different recipes in the same pot," O'Leary said.

IBM's new silicon germanium technology, though, can be meshed with other chips more easily, speeding the development of cell-phones-on-a-chip and other integrated devices, he said.

Consequently, the silicon germanium chips could help the current effort to integrate wireless communication methods such as cellular phones, email, and pagers into a single device.

"It's the usual story. It's bringing down costs, bringing down size," Liebovitch said.

IBM's new chip technology presently is being offered in very basic, high-end commodity parts such as single transistors, voltage-controlled oscillators, and amplifiers. By offering these basic building blocks, IBM is out to prove "that our silicon germanium process is suitable for prime time," O'Leary said.

Silicon germanium technology will be used in equipment made by CommQuest, a wireless communication company IBM bought.