Ge islanding growth on nitridized Si and the effect of Sb surfactant

The growth modes of Ge islands on SiNx-covered Si with and without a surfactant Sb layer are studied by scanning tunnelling microscopy. It is observed that on SiNx/Si(111), Sb cannot enhance the coverage of (I 11) facets of Ge islands, which are the dominant features in the late stage of Ge overlayer growth when Sb is not used. However, on SiNx/Si(001), Sb favours the growth of Ge(001) facets, which will shrink during the islanding growth if Sb is not used. The different behaviours with the (111) and (001) substrates suggest that the surfactant effect of Sb on the islanding growth of Ge on SiNx/Si is strongly orientation dependent