Compositional and spectroscopic study of the growth of diamond films from several gaseous mixtures

A critical experimental test of the empirical unifying scheme recently proposed by Bachmann, Leers, and Lydtyn (1991) about the gas compositions useful to grow diamond films by plasma-assisted chemical-vapor deposition has been performed. The data confirm the main concept of the Bachmann scheme, namely, the existence of a single compositional 'diamond domain' in a C-O-H triangular diagram, in which the overall gas compositions are plotted; however, quantitatively, the shape and the borders of such diamond domain are rather different from those assumed in the work of Bachmann and co-workers. For all the gas mixtures investigated, the changes in the plasma optical emission spectra consequent to crossing the border from the 'no-growth zone' into the 'diamond domain' have been studied. These changes show universal features, which point to the presence of the same growth mechanisms over all the diamond domain, independent of the identity of the initial chemical species.