Proposal of a micro-fabrication process for Al nanostructures

The mechanism of migration of Al adatoms on H-terminated Si(111) surfaces has been investigated by ab initio calculations using density functional theory. The positions of Al adatoms in the potential energy minima and the energy change along the least potential energy path for Al adatom migration have been obtained. Furthermore, we demonstrate the difference between the migration processes on H-terminated and bare Si surfaces. The activation energy required for Al adatom migration has been estimated to be 1.0 eV on bare Si surfaces, but the energy required is very small (2 meV) for Al adatom migration on H-terminated surfaces. Energetic stabilization originating from Al adsorption on H-terminated surfaces is very slight compared with that originating from Al adsorption on bare Si surfaces. Based on these theoretical results, a micro fabrication technique has been proposed for the production of Al nanostructures on H-terminated Si(111) surfaces by selective growth of Al dots only at bare Si areas.