The step-flow growth condition of Si on Si (111) near the (7 x 7)-'' 1 x 1 '' surface phase transition temperature T-C is analysed within the framework of Burton-Cabrera-Frank theory. In particular, coexistence of both surface phases well below T-C and their specific influence on the step-flow growth behaviour is considered. We presume that under dynamical condition of growth, the surface initially covered by only the (7 x 7) phase separates into domains surrounded by '' 1 x 1 '' areas. On such a surface, the overall supersaturation should be reduced drastically compared to a surface with only (7 x 7), resulting in much larger critical terrace width for nucleation. (C) 2015 Elsevier B.V. All rights reserved