PALO ALTO: Not long after Gordon E Moore proposed in 1965 that the number of transistors that could be etched on a silicon chip would continue to double approximately every 18 months, critics began predicting that the era of "Moore's Law" would draw to a close.
More than ever recently, industry pundits have been warning that the progress of the semiconductor industry is grinding to a halt - and that the theory of Moore, an Intel co-founder, has run its course.If so, that will have a dramatic impact on the computer world. The innovation that has led to personal computers, music players and smartphones is directly related to the plunging cost of transistors, which are braided by the billions onto fingernail slivers of silicon - computer chips - that sell for as little as a few dollars each.
But Moore's Law is not dead; it is just evolving, according to more optimistic scientists and engineers. Their contention is that it will be possible to create circuits that are closer to the scale of individual molecules by using a new class of nanomaterials - metals, ceramics, polymeric or composite materials that can be organized from the bottom up rather than the top down.
For instance, semiconductor designers are developing chemical processes that can make it possible to "self-assemble" circuits by causing the materials to form patterns of ultrathin wires on a semiconductor wafer. Combining these patterns of nanowires with conventional chip-making techniques, the scientists believe, willlead to a new class of computer chips, keeping Moore's Law alive while reducing the cost of making them.
"The key is self-assembly," said Chandrasekhar Narayan, director of science and technology at IBM's Almaden Research Center in San Jose. "You use the forces of nature to do your work for you. Brute force doesn't work anymore; you have to work with nature and let things happen by themselves."
To do this, semiconductor manufacturers will have to move from the silicon era to what might be called the era of computational materials. Researchers here in Silicon Valley, using powerful supercomputers to simulate their predictions, are leading the way. While semiconductor chips are no longer being made here, the new classes of materials being developed in this area are likely to reshape the computing world over the next decade.
"Materials are very important to our human societies," said Shoucheng Zhang, a Stanford University physicist who recently led a group of researchers to design a tin alloy that has superconductinglike properties at room temperature. "Entire eras are named after materials - the Stone Age, the Iron Age and now we have the Silicon Age. In the past they have been discovered serendipitously. Once we have the power to predict materials, I think it's transformative."
Pushing this research forward is economics - specifically, the staggering cost that semiconductor manufacturers are expecting to pay for their next-generation factories. In the chip-making industry this has been referred to as "Moore's Second Law."
Two years from now, factories for making microprocessor chips will cost from $8 to $10 billion, according to a recent Gartner report - more than twice as much as what the current generation costs. That amount could rise to between $15 and $20 billion by the end of the decade, equivalent to the gross domestic product of a small nation.The stunning expenditures mean that the risk of error for chip companies is immense. So rather than investing in expensive conventional technologies that might fail, researchers are looking to these new self-assembling materials.
In December, researchers at Sandia National Laboratories in Livermore, Calif., published a paper describing advances in a new class of materials called "metal-organic frameworks" or MOFs. These are crystalline ensembles of metal ions and organic molecules. They have been simulated with high-performance computers and then verified experimentally.
What the scientists have proved is that they can create conductive thin films, which could be used in a range of applications, including photovoltaics, sensors and electronic materials.
The scientists said that they see paths for moving beyond conductive materials, toward creating semiconductors as well.
According to Mark D. Allendorf, a Sandia chemist, there are very few things that you can do with conventional semiconductors to change the behavior of a material. He envisions a future with MOFs in which molecules can be precisely ordered to create materials with specific behaviors.
"One of the reasons that Sandia is well-positioned is that we have huge supercomputers," he said.
They have been able to simulate matrixes of 600 atoms, large enough for the computer to serve as an effective test tube.
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