High temperature chemical vapor deposition of silicon on Fe(100)

Oxidized silicon is a promising candidate for the adhesion promotion of polymeric coatings on iron and steel. Therefore, the surface of iron must be covered by silicon and silicon oxide. This can be done by the chemical vapor deposition (CVD) of silane gas, a process which might be applied in industry easily. Because of these reasons the CVD of Si on the Fe(100) surface was studied at the deposition temperature of 770°C. The silane partial pressure ranged from 0.02 to 0.2 mbar while the total pressure was constant 990 mbar. It was found that the morphology of the surface changes from a very thin two-dimensional (2D)- to a complex and thick three-dimensional (3D)-structure with increasing deposition time. This is connected with a change of the chemical structure and a change in the reaction mechanism. Different processes like passivation of the surface by oxidation and surface diffusion influence the deposition. Models are proposed to describe the mechanism of growth of the surface layer.