Silicon homoepitaxy on high index surfaces and the effect of antimony on this growth

We report on the structure of Si films grown by molecular beam epitaxy on highly misoriented Si(111) surfaces and on the influence of Sb on this growth. Although the equilibrium morphology of these surfaces is a mixture of single and triple height steps, one observes for temperatures lower than the 1 X 1 to 7 X 7 transition one, by LEED, AFM and HRTEM, that the MBE growth gives rise to an important roughness. On the contrary, at higher temperature or when Si and Sb are coevaporated, we stabilize a regular array of steps. We show that these steps are triatomic in the former case and monoatomic in the latter, Such a behaviour illustrates the major role played by the 7 X 7 reconstruction on the growth morphology of Si films.