HOT-FILAMENT CHEMICAL-VAPOR-DEPOSITION DIAMOND GROWTH-KINETICS ON AN EPITAXIAL COSI2 SURFACE MONITORED BY 3 ELECTRON SPECTROSCOPIES

Diamond deposition on an epitaxial CoSi2 layer over Si(111) is precede d by the formation of a 4 nm thick silicon carbide layer. The steps of carbide formation, diamond nucleation and diamond growth are monitore d in situ by three electron spectroscopies (x-ray photoelectron spectr oscopy, Auger electron spectroscopy, and electron-loss spectroscopy). By comparison with our previous studies of diamond growth on clean Si( 100) and Si(111), the time required to stabilize the SiC composition i s much longer. This slow step is interpreted by a strong carbon diffus ion into the bulk which goes together with silicon enrichment of the c arbide phase. The lack of carbon saturation at the surface induces a l arge delay for the subsequent diamond nucleation process by a time sca le factor of 10. In addition, the electron spectroscopy measurements r eveal the appearance of C-C sp(3) species before the diamond nucleatio n starts. These species probably correspond to carbon aggregates which act as precursors of the diamond phase, (C) 1995 American Vacuum Soci ety.