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Apple, Intel and IBM get on GloFlo's SOI bandwagon

by on08 October 2015


FinFETs and SOI working in different environments

Soitec's CEO and board chairman has raised an eyebrow or two when he said that the iPhone 6s has multiple RF chips built on silicon-on-insulator (SOI) substrates and that Intel and IBM are using the tech for their silicon photonics push.


According to EETimes  Paul Boudre, who claimed that SOI is already being used by Apple and Intel even though neither company is broadcasting it. SOI appears to be on track to major market penetration even while the rest of the industry is talking FinFETs.

GlobalFoundries general manager Rutger Wijburg told the SEMICON Europa 2015 that his outfit's 22-nanometer "22FDX" SOI platform delivers FinFET-like performance but at a much lower power point and at a cost comparable to 28-nanometer planar technologies.

The 300-millimeter $250 million FD-SOI foundry here in the "Silicon Saxony" area of Germany, builds on 20 years of GlobalFoundries' investments in Europe's largest semiconductor fabs.

GlobalFoundries said it will extend Moore's Law by using fully-deleted silicon-on-insulator (FD-SOI) transistors on wafers bought from Soitec.

Many had thought that if GloFlo's FD-SOI gamble paid off then it would be a while before FinFET would have a serious rival. But Boudre's claims suggests that SOI is already being used.

Customers like Intel and OEMs supplying fully-deleted silicon-on-insulator (FD-SOI) RF transistors to Apple proves that SOI and Soitec are past the cusp of the growth curve, destined to ramp up exponentially.

The problem for Soitec is no one is really talking about it. Chipzilla is committed to the FinFET, because it is higher performance than FD-SOI, even though it is higher power too.
Boudre said that it was supplying SOI wafers to Intel for other applications that don't require high-performance. For instance, our wafers are very good for their silicon photonics projects.

Apple is already using SOI for several radio frequency (RF) chips in their front-ends, because they use 20-times less power. The iPhone is still using gallium arsenide (GaAs) for its power amplifier (PA) because it needs the high-power device for good connections, but for other RF front-end chips, and in fact for all the chips that they want to keep "always on," the lower power consumption of FD-SOI is pushing the smartphone makers to Soitec, Boudre said.

SOI wafers cost three-times as much as bulk silicon but the cost per die is less because of the simplified processing steps including fewer masks.

Normally GPS chips run on 0.8 volts and consume over 20 milliamps, so they must be turned off most of the time. But when they are made with SOI wafers, they can run on 0.4 volts and consume only 1 milliamp. The mobile device to leave them on all the time and new and more accurate location sensing and new kinds of location-based applications can be developed.

What is amusing then is that Intel's reason for going with FinFETs was that SOI wafers were too expensive but it did find a use for it.

GlobalFoundries' Saxony fab will offer four varieties of its 22FDX process.

  • FDX-ulp for the mainstream and low-cost smartphone market. This will use body-biasing to beat FinFETs on power, but equal them in performance.
  • FDX-uhp for networking applications using analogue integration to match FinFETs while minimizing energy consumption
  • FDX-ull for ultra-low power required by wearables and Internet of Things applications. This will have a 1 picoamp per micron leakage
  • DDX-rfa for radio frequency (RF) analogue applications delivering 50 percent lower power and reduced system costs for LTE-A cellular transceivers, high-order multiple-input/multiple-output (MIMO) WiFi combo chips and millimeter wave radar.
Last modified on 08 October 2015
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