How Small Can You Go?How Small Can You Go?

Researchers at the University of Colorado at Boulder are trying to find out just how small nanotechnology components can get while remaining structurally stable.

Nanotechnology is the field of building microscopic mechanical and electronic devices for a wide range of applications. (A nanometer is one-billionth of a meter.) Faculty in the university's mechanical engineering department, using advanced simulation capabilities, are concentrating on multilayer microelectrical-mechanical systems that combine the functions of mechanical devices and electronic circuits. They've designed microscopic fans with blades less than half a millimeter in length for cooling super-fast semiconductors.

They've also been focusing on how to test the reliability of nanotechnology. One area of study has been the stresses between layers of gold-silicon and aluminum-silicon films used to manufacture nanoswitches for optical communications networks, associate professor Martin Dunn says. "We hope to get a clear understanding of what the operational failure modes are of these nanoscale structures," he adds.

Using visualization software from Computational Engineering International, the scientists are creating simulations of how the atoms in microelectrical-mechanical systems behave when subjected to changing temperatures. That's not easy: To model the effect of forces on a 0.1-micron cube, the scientists must calculate the attractive-repulsive forces and energy interactions among nearly 15 million atoms.

It's hoped the research leads to micromodeling techniques for testing the reliability of these systems. The project is expected to continue for three years, Dunn says. It's funded, in part, with a $400,000 grant from the National Science Foundation and Sandia National Laboratories.