Computer chips brought down to size

A computer chip the size of a postage stamp could soon have the power of 1,000 personal computers, say Cambridge scientists.

This is because scientists have made a breakthrough in which they can get a single electron to perform calculations, instead of the large numbers of electrons necessary in today's computer chips.

Chips are crammed full of transistors, which contain the electrons that store information and do calculations. The number of transistors that can be squeezed on to a chip has increased phenomenally but is reaching a bottleneck. Scientists have been searching for a way of decreasing the number of electrons needed, and so far have reduced them from ten million to ten thousand per transistor.

But the new research completely changes the way in which electrons store and process information. The scientists, from the Microelectronics Research Centre of the Cavendish Laboratory and the Hitachi Cambridge Laboratory, announced two years ago that they could use single electrons to store information - single electron memory. Now they have managed to get the single electrons to process the information as well.

"We can now do any kind of operation in mathematics," said Yutaka Kuwahara, general manager at Hitachi Europe's Research and Development Centre.

"The age of the single electron device is a stage nearer. It has capabilities almost like the human brain."

Kazuo Nakazato, one of the two scientists who made the breakthrough, said that they could store the equivalent of "ten million doubled-spaced type- written pages of text on an area the size of a postage stamp. By adding single-electron logic, however, we can construct a huge information processing system within a similar sized chip".

Haroon Ahmed, professor of microelectronics at Cambridge said that they are working with the devices at minus 200 C. "We have encouraging results to lead us to believe that we can get to room temperature. But it is not certain," he said.