Vicinal Si(001) surfaces with ≈4° miscut toward [110] consisted of ordered terraces that were separated by a double step every 4nm. Adsorption of Au at 800 to 900C changes the step morphology dramatically: after a critical Au coverage of 1/3ML was reached, Au condensed from an initially formed lattice gas into a (5 x 3.2) reconstruction on newly formed (001) terraces. The steps of the vicinal surface were accumulated in irregular step bunches to conserve the macroscopic miscut. With increasing Au coverage the step bunches were transformed into well-defined facets. The ultimate facet orientation depends on the adsorption temperature, although at temperatures above 800C only (001) terraces and (119) facets were observed. Depending on the deposition temperature, the terraces and facets exhibited a periodicity from 200nm to 4µm and a structural length of up to several millimetres. Illumination with white light under grazing incidence results in a colourful striped pattern in an optical microscope. A novel in situ light diffraction experiment was presented, that was perfectly matched to the mesoscopic dimensions of the faceted surfaces. Illumination with a He–Ne laser during and after deposition results in complex diffraction patterns that could be used to estimate the length of the terraces. The temperature dependence of the terrace length showed an Arrhenius behaviour with an activation energy of EA ≈ 2.8eV during the initial stages of the faceting; at 825C the terraces extend with a constant velocity of 30µm/s. This value was in excellent agreement with earlier low energy electron microscopy measurements.

Analysis of Mesoscopic Patterns Formed by the Au-Induced Faceting of Vicinal Si(001). F.J.Meyer zu Heringdorf: Journal of Physics - Condensed Matter, 2006, 18[13S], 1-15