title: Nucleation of Ga droplets on Si and SiOx surfaces.
abstract: We report on gallium droplet nucleation on silicon (100) substrates with and without the presence of the native oxide. The gallium deposition is carried out under ultra-high vacuum conditions at temperatures between 580 and 630 °C. The total droplet volume, obtained from a fit to the diameter-density relation, is used for sample analysis on clean silicon surfaces. Through a variation of the 2D equivalent Ga thickness, the droplet diameter was found to be between 250-1000 nm. Longer annealing times resulted in a decrease of the total droplet volume. Substrate temperatures of 630 °C and above led to Ga etching into the Si substrates and caused Si precipitation around the droplets. In contrast, we obtained an almost constant diameter distribution around 75 nm over a density range of more than two orders of magnitude in the presence of a native oxide layer. Furthermore, the droplet nucleation was found to correlate with the density of surface features on the 'epi-ready' wafer.
authors.affiliation: Center for Micro- and Nanostructures and Institute for Solid-State Electronics, Vienna University of Technology, Floragasse 7, A-1040 Wien, Austria. Austrian Academy of Sciences, Dr. Ignaz Seipel-Platz 2, A-1010 Wien, Austria.
authors.forename: H
authors.initials: H
authors.lastname: Detz
authors.forename: M
authors.initials: M
authors.lastname: Kriz
authors.forename: D
authors.initials: D
authors.lastname: MacFarland
authors.forename: S
authors.initials: S
authors.lastname: Lancaster
authors.forename: T
authors.initials: T
authors.lastname: Zederbauer
authors.forename: M
authors.initials: M
authors.lastname: Capriotti
authors.forename: A M
authors.initials: AM
authors.lastname: Andrews
authors.forename: W
authors.initials: W
authors.lastname: Schrenk
authors.forename: G
authors.initials: G
authors.lastname: Strasser