Diamond nucleation suppression in chemical vapor deposition process

A systematic study of the effect of different pre-treatments of the Si subs trate surface in suppressing diamond nucleation was performed to investigat e the nature of the nucleation centers in chemical vapor deposition (CVD) o f diamond. The Si substrates were initially scratched with diamond powder a nd then submitted to one of the following pre-treatments: thermal annealing in high vacuum and in air, deposition of an amorphous silicon film, and Kr -84(+) ion implantation. The pre-treated substrates were used in a hot fila ment CVD diamond process, and the diamond films obtained were analyzed by d ifferent techniques. The results suggest that the observed nucleation reduc tion under certain pre-treatment conditions is related to modifications ind uced on the original topographical features of the scratched substrate surf ace, which would be responsible for the CVD diamond nucleation. The dimensi ons of these surface features are estimated to be of the order of 5 nm. (C) 1999 Elsevier Science S.A. All rights reserved.