IBM launches shipping silicon-on-insulator CPUs

IBM today launched a line of new servers based on processors built using the company's silicon-on-insulator technology.

OK, so the servers are just an extension to Big Blue's AS/400 line - the AS/400e 800, to be specific - but today's announcement marks the first step in getting the performance-boosting technology into more mainstream CPUs.

SOI works by placing the chip's components not onto silicon but on a layer of silicon dioxide - glass, to the rest of us. The idea here is to prevent electrons seeping out of transistors and all the reduction in signal that such seepage introduces. This effect is becoming increasingly problematic to chip designers as transistors sizes - and thus the number of electrons they can contain - continue to shrink.

Fixing those leaking 'lectrons will lead to a 20-30 per cent performance improvement, reckons IBM, presumably by enabling smaller chips to operate at higher clock speeds.

There's no such thing as a free lunch, however, and the downside to SOI is the need to completely redesign any chip that uses the technology. Designers can't simply churn out existing silicon layouts for SOI production. The glass layer also has to be of exceptional purity.

For these kinds of reasons, SOI is unlikely to make it into mainstream chips for some time yet. However, IBM's PowerPC partner (when they're not arguing with each other, that is), Motorola, is almost certainly evaluating the technology for its own CPUs. Texas Instruments and Hewlett-Packard are also said to be taking a close look at it, according to sources cited by CNet. In HP's case that could even see the technology being used in its upcoming PA-8700 processor.

Eventually, IBM believes, others will sign up too: "We think this is going to be a pervasive technology around the industry," IBM Semiconductor R&D head Bijan Davari told CNet. "The industry will move to it - it's just a matter of time." ®