Kinetic model for diamond nucleation upon chemical vapor deposition

摘要

A kinetic model for diamond nucleation on an Si substrate upon chemical vapor deposition has been proposed, based on a surface reaction mechanism. Considering the atomic hydrogen etching effects on the Si substrate and the stable atomic cluster with diamond structure, a growth rate equation describing diamond nucleation was constructed, and from the time-dependent solutions of this equation, an important nucleation behavior was found that the atom amount, which the stable atomic cluster with diamond structure contains, exists the maximum value in the deposition process of the cluster. Accordingly, 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 upon chemical vapor deposition. On the other hand, diamonds may not be nucleated permanently in the deposition process if the maximum value of the atom amount of the stable clusters do not reach the amount required by the diamond critical nucleus at the initial stage in the deposition. These theoretic results reasonably explained the relevant experimental observations of diamond nucleation on Si substrates and revealed some important kinetic mechanisms of diamond nucleation upon chemical vapor deposition.