Arsenic interaction with vicinal Si(001) surfaces

Abstract The influence of As on the step structure and terrace distribution of Si(001) vicinal surfaces has been studied on a lens-shaped sample by high-resolution LEED and Auger electron spectroscopy. In the [110] azimuth, the formation of the two As adsorbate-configurations (1 ML As, As dimers parallel and perpendicular to the double layer step edges) was reproduced. Upon annealing to 970 K, the step structure changes without significant As desorption. Both for vicinals up to 10° in the [110] azimuth and 6° in the [100] azimuth, high steps of four layers are formed (F-steps). Everywhere, (2 × 1) and (1 × 2) domains are equally distributed, indicating no preferential orientation of the As dimers with respect to the edges. The F-step pattern is not very well ordered. The spot profiles suggest meandering with a local step orientation preferentially towards equivalent 〈110〉 azimuths. Annealing to 1070 K leads to an As coverage of 1 4 ML, connected with a c(4 × 4) reconstruction on (001) and all vicinals.