Nano-patterned silicon surfaces for the self-organised growth of metallic nanostructures

Abstract The aim of this work is to obtain a very regular alignment of metallic and magnetic nanostructures with high density and a narrow size distribution via a self-organised growth process. The method consists of combining microelectronic processes which will provide a periodic surface pattern, with self-assembled growth on the so-obtained surface. The structured surface serves as a template for the controlled positioning of the nanostructures. Concerning the silicon template preparation, the surface periodicity should be of the same order of magnitude as the atomic surface diffusion length used during subsequent growth. These surface patterns were obtained on vicinal silicon surfaces by optimising electron-beam nanolithography and reactive ion etching, to create arrays of nano-holes typically 50 nm in diameter with a 50 nm spacing. A subsequent sample annealing under ultra-high vacuum conditions is studied in order to obtain a corrugated surface mimicking the lithography pattern. As a model system, the growth of Au on vicinal Si(111) surfaces has been chosen. After high temperature annealing, clean Si surfaces present arrays of straight step bunches each separated by ∼50 nm. We discuss the formation of Au islands on these step bunches during growth and/or annealing at a temperature between 300 and 500  ∘ C.