DIAMOND NUCLEATION ON PRETREATED SUBSTRATES

Diamond particles were grown on normal silicon substrates, iron-coated substrates, and carbonized substrates in a methane atmosphere. The iron thin film deposited onto the silicon substrate influenced diamond nucleation and the subsequent growth of diamond particles. The diamond nucleation density was enhanced by the iron film. X-ray photoelectron spectroscopy analysis of the substrate surfaces revealed that the diffusion of carbon atoms into the substrate and the formation of an SiC layer on the substrate surface are important in the diamond nucleation process. Iron has a high diffusion coefficient of carbon atoms, including carbon molecules on the silicon substrate surface, and helps to produce the carbide layer on the substrate. The nucleation density of diamonds was also measured to study the role of the carbide layer and the pretreatment of substrates in diamond nucleation. Pretreatment of the substrates for carbonization of the substrate surface also enhances the diamond nucleation density on both the normal silicon and Fe/Si substrates. This suggests that carbon diffusion into the substrates and carbide reaction occur at the substrate surface to produce diamond nucleation sites.