Kinetic model for diamond nucleation upon chemical vapor deposition

A kinetic model for diamond nucleation on an Si substrate upon chemical vap or deposition has been proposed, based on a surface reaction mechanism. Con sidering the atomic hydrogen etching effects on the Si substrate and the st able atomic cluster with diamond structure, a growth rate equation describi ng diamond nucleation was constructed, and from the time-dependent solution s of this equation, an important nucleation behavior was found that the ato m amount, which the stable atomic cluster with diamond structure contains, exists the maximum value in the deposition process of the cluster. Accordin gly, this means that the nucleation formation of diamond films could occur if the maximum value of the atom amount of the stable cluster with diamond structure arrive at the amount required by the diamond critical nucleus upo n chemical vapor deposition. On the other hand, diamonds may not be nucleat ed permanently in the deposition process if the maximum value of the atom a mount of the stable clusters do not reach the amount required by the diamon d critical nucleus at the initial stage in the deposition. These theoretic results reasonably explained the relevant experimental observations of diam ond nucleation on Si substrates and revealed some important kinetic mechani sms of diamond nucleation upon chemical vapor deposition. (C) 2000 Elsevier Science S.A. All rights reserved.