Abstract A model is proposed for doping of silicon layers during homoepitaxy on a substrate slightly tilted from the (110) plane. The model suggests a dual mechanism of layer growth both by nucleation and trapping of silicon adatoms in geometrical growth sites (steps) on the surface, and is analysed by means of the method of correlation functions of atoms near the growth sites. It is shown that possible regimes of doping are governed by the competition, first, between desorption of impurity and its incorporation into the layer and, second, between “blocking” of the impurity adatoms near the steps and their absorption by the surface vacancies. Formulae are obtained which relate the steady concentration of the impurity in the layer and the width of transition concentration regions to the substrate temperature, growth rate, the misorientation angle of the substrate and the density of the impurity beam from the source. The conditions for 100% impurity transfer from the source into the layer are predicted. The obtained results are in good agreement with previously published experimental data.