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Scientists seek diamond computer chip

Only a few are singing about them yet, but it could turn out that diamonds are a computer's best friend.
/ Source: Reuters

Only a few are singing about them yet, but it could turn out that diamonds are a computer's best friend.

Damon Jackson is one researcher who sees the sparkling gems as a way to overcome the limitations of the silicon chips that serve as the brains of computers and the machines they run.

"It's not a pie-in-the-sky idea," said Jackson, who works in the Lawrence Livermore National Laboratory east of San Francisco.  "I would not be surprised at all, as more people start to look into this, if five or 10 years down the line that diamond would be a common material in a computer."

He showed off a microscope focused on a $1,500 natural diamond topped with a spiral of electronic circuits.  On a second diamond, eight circuits pointed upward to the summit.

Electronics and the most treasured of jewels may appear an unlikely marriage but for the shortcomings of today's chips and new advances in creating diamonds.

A conventional computer chip is a slab of silicon topped with millions of transistors -- tiny switches that provide the computing power as electricity passes through them.  That blitz of electricity produces heat, a scourge of chip designers that may halt progress in making faster silicon semiconductors after a decade or so.

Diamond supremacy?
Enter the diamond, which already has a major presence in manufacturing because of its strength and extremely high melting point.

"You can operate a diamond-based transistor at higher temperatures than you could a silicon-based transistor," said John Venables, an advisor at the Pentagon's Defense Advanced Research Projects Agency.

Venables was already predicting diamond computer chips in 1990, when he headed a National Academy of Sciences study.  Skeptics say the failure of such expectations to materialize points to the significant obstacles in making diamond chips.

"It's not on the mainstream radar screen," said Pushkar Apte, vice president of technology programs at the Semiconductor Industry Association in San Jose, California.

Even now, Venables does not expect home computers to carry stickers saying "diamond inside" any time soon.  Instead, he sees diamond chips in specialized devices like satellites, which have difficulty disposing of heat in space.

The price of such chips remains potentially daunting, but scientists hope new techniques in man-made diamonds will lower costs.  "The initial cost is huge," Jackson said at Livermore. "Once it works, your cost per unit drops."

Jackson starts his work with a natural one-third carat diamond.  Once he has put the circuits on it, he sends it to the University of Birmingham in Alabama, where Professor Yogesh Vohra patented a process to grow diamonds by essentially cooking methane and hydrogen gases in a very hot microwave oven.

Vohra seals the Livermore jewel with a man-made diamond layer.  He foresees the eventual development of an entirely man-made diamond chip with the circuitry also made of diamonds.

"What we have done with Livermore is show that we could embed the electrical circuits on a high-quality diamond," he said, adding that engineering challenges make a full diamond chip unlikely before five or 10 years.

Serious work on manufactured diamonds dates back half a century, but scientists have seen growing success in recent years. Several private companies are already marketing the man-made gems.

Scientists are also working on using other materials -- including other carbon-based compounds -- to allow for continued fulfillment of Moore's Law, which predicts that computing power will double roughly every two years.

With current technology, "we are rapidly approaching the time when the laws of physics will limit our implementation of Moore's Law," Semiconductor Industry Association President George Scalise said recently.  "We are now in a worldwide race to develop new technologies that will enable progress in semiconductor devices to continue at the pace we have seen for nearly 40 years."