In this paper, two distinct studies are presented: Sb adsorption on Si 〈111〉 analyzed by both ellipsometry and electron diffraction in real time, and Sb doping in Si molecular-beam epitaxy (MBE). In the adsorption study, saturation is shown to occur at one monolayer of equivalent silicon. Superstructures do not appear at the same coverages and temperatures during adsorption and desorption. It is also confirmed that the anomalies we have previously observed in the desorption kinetics are due to superstructures. A detailed study of the sticking coefficient explains both the differences in adsorption and desorption phase diagrams and the complex evolution of Sb doping in Si MBE. Variations of the doping level with the growth rate and incident dopant flux support this result.