Carbon chips offer gecko strength

01 Feb 2006 View Comments
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What do pencils, diamonds and computer memory all have in common? It turns out that soon all three may be made from the same basic material, which is carbon.
We are about to see a massive technology shift in the field of computer hardware.

Later this year a few vendors, including an American chip cutter called Nantero, will start offering dual in-line memory modules (Dimms) built with a new material called carbon nanotubes, sometimes also referred to as buckytubes.

Further reading

If you’ve never come across them, carbon nanotubes are extremely small cylinders made up of carbon atoms – they’re about 50,000 times thinner than a human hair.

Although they don’t occur naturally, they have similar properties to setae, which are those tiny hairs on the feet of gecko lizards. Actually, the ends of setae split into many nanoscale fibres called spatulas, and these spatulas are so fine that they form molecular bonds with almost anything they touch. Those bonds allow geckos to climb walls and hang from a pane of glass.

Carbon nanotubes are about 200 times more sticky than the gecko’s foot hairs, and their semiconducting nature is being exploited to make memory chips. To put it somewhat crudely, these work by slinging tiny mats of carbon nanotubes between lumps of silicon inside a chip to form very small bridge-like structures.

Those bridges hang over another layer of silicon, and can be electrically controlled either to float above the silicon base or to hang down and touch it. Once they touch the base they stick to it in much the same way the gecko’s feet stick to stuff. This binary action is being applied to make computer memory chips with interesting properties. For example, such RAM chips can read or write a binary digit – bit – in as little as half a nanosecond.

The best RAM chips today need about 10 nanoseconds to do the same thing. The coming chips can’t walk up walls, but they can retain information without requiring the near constant electrical refresh cycles associated with current DRAM technologies. This could mean big power savings compared with current Dimms, and computers that go instantly into a standby mode and stay there for years without needing a power supply.

In 2003, one gram of carbon nanotubes would set you back between twenty and one thousand Euros, depending on the purity. Since then prices have fallen to an acceptable level for many applications.

So it seems the stage is set for a new class of computer processors that could enable extremely high-density RAM chips, meaning bigger memories for more powerful servers. Those chips would use less power, making datacentres cooler. And they would enable computers to switch on in an instant, which could be good for everyone.

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