Intelligent Machines

Computing beyond Silicon

  • by Katherine Bourzac
  • April 20, 2010
  • The logic gate relies on carbon nanotubes. The nanotubes are the faint vertical lines stretching between the circuit traces.

It is inevitable that eventually Moore’s Law will fail–at least for silicon technology. Further miniaturizing silicon transistors to fit more of them on a microchip will become impossible, or at least too expensive. Researchers are anticipating that day by developing alternative materials such as gallium arsenide, graphene, and carbon nanotubes. The hope is that transistors made from these materials will be smaller, faster, and more energy efficient than anything that could ever be made from silicon. “We need to add more materials to the toolbox,” says Michael Mayberry, director of components research at Intel.

One challenge is to make these materials work with the infrastructure built for silicon, which represents billions of dollars in investment for chip makers (see “The High Cost of Upholding Moore’s Law”). Intel, for one, has developed expertise in compound semiconductors, such as gallium arsenide, that operate at higher speeds and lower voltages than silicon. But gallium arsenide is brittle, so devices made from it are difficult to manufacture in volume. Intel is trying to get around the problem by growing thin layers of this material on top of silicon wafers, hoping to improve silicon chips by adding a few high-­performance gallium arsenide elements.

Other major contenders to replace silicon are based on carbon. In February, IBM made transistors from graphene, a one-atom-thick mesh of carbon; they are much faster than silicon transistors, switching at the rate of 100 gigahertz. Crucially, the IBM researchers built the transistor arrays on wafers, using a manufacturing-friendly process. These graphene transistors are still much bigger than their silicon counterparts, however, and an integrated circuit hasn’t been made from them yet.

This story is part of our May/June 2010 Issue
See the rest of the issue
Subscribe

Researchers are also working on making transistors from carbon nanotubes. Like the graphene transistors, these are speedy, but they are much smaller. At Stanford University, scientists are developing techniques for fabricating three-dimensional integrated circuits based on these cylindrical molecules of carbon.

It’s still uncertain what will ultimately replace silicon. But this once dominant material is already looking too fragile, too power hungry, and too expensive to drive our computers forever.

Want to go ad free? No ad blockers needed.

Become an Insider
Already an Insider? Log in.

Uh oh–you've read all of your free articles for this month.

Insider Premium
$179.95/yr US PRICE

More from Intelligent Machines

Artificial intelligence and robots are transforming how we work and live.

Want more award-winning journalism? Subscribe and become an Insider.
  • Insider Premium {! insider.prices.premium !}*

    {! insider.display.menuOptionsLabel !}

    Our award winning magazine, unlimited access to our story archive, special discounts to MIT Technology Review Events, and exclusive content.

    See details+

    What's Included

    Bimonthly magazine delivery and unlimited 24/7 access to MIT Technology Review’s website

    The Download: our daily newsletter of what's important in technology and innovation

    Access to the magazine PDF archive—thousands of articles going back to 1899 at your fingertips

    Special discounts to select partner offerings

    Discount to MIT Technology Review events

    Ad-free web experience

    First Look: exclusive early access to important stories, before they’re available to anyone else

    Insider Conversations: listen in on in-depth calls between our editors and today’s thought leaders

  • Insider Plus {! insider.prices.plus !}* Best Value

    {! insider.display.menuOptionsLabel !}

    Everything included in Insider Basic, plus ad-free web experience, select discounts to partner offerings and MIT Technology Review events

    See details+

    What's Included

    Bimonthly magazine delivery and unlimited 24/7 access to MIT Technology Review’s website

    The Download: our daily newsletter of what's important in technology and innovation

    Access to the magazine PDF archive—thousands of articles going back to 1899 at your fingertips

    Special discounts to select partner offerings

    Discount to MIT Technology Review events

    Ad-free web experience

  • Insider Basic {! insider.prices.basic !}*

    {! insider.display.menuOptionsLabel !}

    Six issues of our award winning magazine and daily delivery of The Download, our newsletter of what’s important in technology and innovation.

    See details+

    What's Included

    Bimonthly magazine delivery and unlimited 24/7 access to MIT Technology Review’s website

    The Download: our daily newsletter of what's important in technology and innovation

/
You've read all of your free articles this month. This is your last free article this month. You've read of free articles this month. or  for unlimited online access.