Group makes advance in microchip research

An NUI Dublin research group has succeeded in "growing" silver wires a million times thinner than a penny. Its work could revolutionise the microchips which power modern computers, allowing much smaller, lighter devices.

The research, by the Nano chemistry Group, is published this morning as the cover story in the leading international journal, Advanced Materials. The wires are seven-billionths of a metre across (seven nanometres, also written nm). Current microchip technology produces wires about 250nm across and routine random access memory chips use connections about 500nm across.

The technology involves getting small "nanoparticles" of the metal to organise themselves into wires, explained Dr Donald Fitzmaurice who heads the group and who carried out the research with colleague Dr Brian Korgel.

"If you prepare these [nanoparticles] in a special way and select out particles of a particular size and shape, you can put them in solution, evaporate off the liquid and they will self-organise into thin wires," Dr Fitzmaurice said.

The particles are of a similar size and shaped like eggs. The electrical charges and forces around them cause them to line up side to side into rows, forming a wire. The attractive forces are stronger at the sides than at the ends so the metal "eggs" touch at their sides but not at their ends, forming distinct, separate wires of metal.

In effect the group was able to "programme" a nanoparticle to recognise and selectively bind to the nanoparticle next to it, he said. The process is very cheap and wires can be put together in about half an hour. A student could learn to do it in about a day so the technology would be simple to apply.

Dr Fitzmaurice said it would take time to establish how his new nanowires would perform if integrated into a chip.