Résumé
We have investigated the role of microscopic defects, which usually are present at very low density in the thin silicon overlayer (SOL) of SIMOX wafers, on the final structural properties of b-SiC grown on top of this material. To modify the defects density we have used different wafers with SOL thickness of 150, 100 and 50 nm, respectively. After SiC deposition, we have found that the density of defects (mainly holes running through the SiC films and underlying cavities) follows, roughly speaking, the concentration of initial defects in the SOL. Taking into account the diffusion of atomic species and the different possible chemical reactions, the microscopic mechanism of holes and cavities formation is discussed.