Development of different carbon phases during diamond film growth by CVD on glassy carbon substrates

Th epaper reports on the structural investigation of different carbon phases generated during the hot filament chemical vapour deposition (HFCVD) of diamond films on glassy carbon substrates. The reflection high energy electron diffraction (RHEED) analysis, performed on both front- and back-side of the removed film and on the substrate surface before and after the coating process, enabled to identify four distinct carbon phases in the transition from glassy carbon to Fd3m cubic diamond structure. In particular the present investigation revealed the occurrence, in the bottom layer of the film, of a face-centered-cubic diamond polytype (X-diamond) belonging to the space group F4-3m. The findings of our research seem to indicate an evolution of carbon species towards lattices with increasing symmetry.