X-RAY PHOTOELECTRON-SPECTROSCOPY OF INITIAL-STAGES OF NUCLEATION AND GROWTH OF DIAMOND THIN-FILMS DURING PLASMA ASSISTED CHEMICAL VAPOR-DEPOSITION

We have carried out x-ray photoelectron spectroscopy on diamond thin films deposited by microwave assisted chemical vapor deposition technique using a H-2-CH4 plasma. Films grown for different lengths of time, from 1 min to several hours, were analyzed for the surface composition in the C 1s and Si 2p regions. The results indicate the presence of SiC in the initial stage of nucleation due to the carbon interaction with the Si substrate. Graphite starts to form in early stages of nucleation as the substrate becomes supersaturated with carbon. A diamond peak starts to appear after the incubation period and a simultaneous decrease in the carbide and graphite peak intensities was observed. Graphite is preferentially etched during the growth but SiC remains as an impurity even after several hours of deposition.