Monday, July 18, 2005

"NANOTECH: Work eyes angstrom-scale wafer patterning"

As major semiconductor fabs tackle the submicron nanoscale patterning of wafers, researchers at Pennsylvania State University have already moved to the angstrom scale. Their organic monolayers with 5-angstrom features promise to enable the self-assembly of patterns too small for lithography by serving as templates for chip atoms. "We use molecules that are deliberately designed to be less stable in their substrate attachment than other related molecules, so they would be unlikely to be used directly," professor Paul Weiss said. "Rather, they will be used to shore up patterns and to stabilize the precision of the patterns at this subnanometer scale." Self-assembled monolayers (SAMs) offer a way to create intricate angstrom-scale patterns that can be tuned by adjusting their chemical makeup and thereby precisely adjusting their resulting physical properties. Using these patterns, which serve as placeholders, single-molecule devices can potentially be arrayed across wafers. The SAMs consist of adamantanethiol, a commonly used organic molecule for this kind of work. Weiss' group is developing a catalog of useful chemical formulas that can create a variety of self-assembled monolayers that serve as patterns for single-molecule semiconductor devices.