A COmparison of the CVD Diamond Nucleation and Growth Processes on pristine Silicon and Copper Monocrystals

摘要

CVD diamond synthesis is now well etablished. However, main diamond applications require a better control of the nucleation and growth mechanisms. At the early stages, there is a strong competition between diamond nucleation nad carbon phases fromation. We show that the nucleation, studies by electron spectroscopies, SEM, HRTEM and AFM, is quite very different dependingon hte substrate. O silicon surfaces, a carbide layer of 1-2 nm thick is formed within the first minutes of deposition. Furthermore, an etchingprocess by the radical hydrogen occurs, inducing surface defects, possible preferential sites for the diamond nucleation. On copper, where no carbon miscibility occurs, oriented turbostratic graphite layers are stabilized duringhe early stages of deposition. Then , we evidence the formation of many carbon forms before diamond nucleation. Some of them are quite new andcould constitute precusors of the diamond nuclei.