IBM fabs 90nm G5 using strained silicon

Better results than Intel, ahem...

  • alert
  • submit to reddit

IBM's first 90nm chip, the G5-class PowerPC 970FX, incorporates a key technique used by Intel to improve processor performance, it has emerged, courtesy of a small mention tucked away at the end of a Reuters story.

Like Intel's Prescott Pentium 4, the 970FX uses Strained Silicon. By stretching - or 'straining', as it's called in the trade - a lattice of silicon atoms, chip makers improve the ability of electrons to flow through the semiconducting material.

Transistors made from strained silicon are said to get a 35 per cent performance boost over regular transistors of the same size.

The technique works by adding a layer of silicon over a layer of silicon germanium (SiGe). The top layer's silicon atoms align themselves with those in the SiGe layer's wider-spaced crystal lattice, pulling them apart. The trouble is - as Intel has found - that it's hard to integrate the addition of that SiGe layer into existing fabrication processes.

Now, where IBM differs from Intel is in the use of silicon-on-insulator (SOI), which conveniently aids the implementation of strained silicon. As it announced last September, IBM removes the SiGe layer before fabrication, after applying the strained silicon onto the insulator. The upshot: it gains benefits of strained silicon using what is essentially its standard SOI process. By removing the SiGe layer, it doesn't have to integrate that material into the chip fabrication process per se. It calls the new technique, Strained Silicon Directly on Insulator (SSDOI).

The presence of strained silicon in addition to SOI may well explain how IBM has been able to bring the 970FX's power consumption to well below that of the 130nm 970 - in direct contrast to Prescott, which, clock for clock, has a higher power consumption than its 130nm predecessor, Northwood. ®

Related Stories

IBM 90nm G5 chip to 'outrun' Prescott, Athlon 64
IBM claims massive power cut for 90nm G5
IBM to add clock throttling tech to 90nm G5 chip
IBM boffins boost chip performance by 65%
Xbox 2 to sport three 64-bit IBM chips, ATI R500


Secure remote control for conventional and virtual desktops
Balancing user privacy and privileged access, in accordance with compliance frameworks and legislation. Evaluating any potential remote control choice.
WIN a very cool portable ZX Spectrum
Win a one-off portable Spectrum built by legendary hardware hacker Ben Heck
Intelligent flash storage arrays
Tegile Intelligent Storage Arrays with IntelliFlash helps IT boost storage utilization and effciency while delivering unmatched storage savings and performance.
High Performance for All
While HPC is not new, it has traditionally been seen as a specialist area – is it now geared up to meet more mainstream requirements?
Beginner's guide to SSL certificates
De-mystify the technology involved and give you the information you need to make the best decision when considering your online security options.