Researchers attempting to find cheaper and more effective ways to reduce the size of computer microchips are calling on an unlikely material in their quest: aluminum.
Normally associated with faulty wiring from the 1960s and '70s, aluminum has proven an effective catalyst in building silicon nanowires, a key element of cutting-edge microchips, according to a study released by the Max Planck Institute for Microstructure Physics on Wednesday.
Silicon, a semiconductive material, is the key component of transistors in today's super-fast microchips.
Computer researchers have been searching for a method of creating silicon wires just nanometres thick to greatly reduce the size and increase the power of chips.
Theyare also under pressure to keep alive the popular formulation of Moore's Law, which says that computer chip power should double every 18 months.
To construct silicon nanowires, scientists have been working with gold as a catalyst because it is resistant to external effects but can be heated at relatively low temperatures. Other materials such as copper require much greater heat to break down.
Nanowires are created by placing a thin film of gold on a silicon surface and heating it. When the film breaks down, a gas containing siliconis directed to the surface and it reacts with the gold catalyst.
The silicon dissolves into the gold particle and when the gold cannot absorb any more, the silicon crystalizes underneath. This ultimately creates a thin crystal silicon nanowireon the surface.
Using aluminum instead of gold makes the nanowires more suitable for the microchip industry,the researchers said.
Gold particles can interfere with the process of etchingmaterial onto a microchip, while aluminum has less chance to do so when oxygen is removed.
Creating such an oxygen-free environment in the chip would be essential when using aluminum, since aluminum's relatively quick oxidation is one of the reasons it failed to last as a material for wiring four decades ago.
The researchers see possibilities for the new process beyond computers.
"Apart from the possibility of using them in the semiconductor industry, the nanowires are very interesting for basic research, as little is as yet known about their properties and their growth," said Dr. Stephen Senz, one of the scientists involved.