The early stage of 3C-SiC nucleation and islands enlargement on on-axis 6H-SiC(000 (1) over bar) (C face) were studied by changing the conditions of interaction of a Si0.25Ge0.75 melt with the SiC substrate. After changing the temperature or the plateau duration at a fixed temperature, evolution in terms of shapes and sizes of the 3C-SiC islands was found. The observed islands enlargement in the early stage of interaction was explained by taking into account a carbon transport from the graphite crucible to the seed. Once the crucible reached its thermal and thermodynamical equilibrium with the liquid, the islands started to be dissolved inside the melt due to a possible but small thermal gradient from the seed (hotter) to the sidewalls of the crucible (colder). By adding propane in the gas phase before reaching this equilibrium, SiC growth by vapour-liquid-solid (VLS) mechanism was achieved and the 3C-SiC layers thus obtained were always found to contain a high density of twins. This is probably due to the fact that the density of 3C nuclei, after interaction between the SiGe melt and the SiC seed, was always very high which should prevent orientation selection, unlike the case of Si face. (c) 2009 Elsevier B.V. All rights reserved.