HFCVD DIAMOND GROWTH ON CU(111) - EVIDENCE FOR CARBON PHASE-TRANSFORMATIONS BY IN-SITU AES AND XPS

Polycrystalline diamond has been deposited on monocrystalline Cu(lll) via the hot filament chemical vapour process. The diamond growth was s tudied by Auger electron spectroscopy (AES) and X-ray photoelectron sp ectroscopy (XPS), directly connected to the growth chamber. Shape anal ysis of the AES CKVV line and C Is relative intensity both suggest the following three-step process: first the formation of two graphite lay ers, then the very slow growth of graphitic layers, more and more dist orted when going away from the copper surface and finally, when a crit ical size corresponding to ca five to six layers is reached, diamond n ucleation and growth. A very long induction time (> 10 h) is observed before the growth of graphitic layers. This is ascribed to the strong interaction of the graphite layer with the copper surface. Transmissio n electron microscopy and selected area diffraction confirm this proce ss, but in addition reveal the presence of small spherulitic (onions) and polyhedral graphite-like aggregates. This nucleation process is ro ughly in agreement with the recrystallization model of diamond nucleat ion from amorphous carbon proposed by Singh and Vellaikal, (C) 1997 El sevier Science B.V.