ANALYSIS USING HIGH-ENERGY BEAM TECHNIQUES OF THE SURFACE CARBONACEOUS LAYERS OF SILICON AND TANTALUM SUBSTRATES USED IN THE CHEMICAL-VAPOR-DEPOSITION SYNTHESIS OF DIAMOND

Data on the elemental composition and thickness of the carbonaceous layers generated during hot-filament chemical vapour deposition of diamond on Si(100) and polycrystalline tantalum substrates were gathered by the combined use of Rutherford backscattering spectrometry (RBS) carried out with H-1+ and He-4+ beams and nuclear reaction analysis employing the C-12(d,p)C-13 reaction. Determination of the layer thicknesses required the combined use of RBS and secondary ion mass spectroscopy analysis in depth profiling mode. The total amount of carbon deposited onto the substrates was found to depend on the process temperature, following different trends for silicon and for tantalum. The amounts of hydrogen and oxygen incorporated in the deposits were measured by the reactions H-1(N-15,alpha gamma)C-12 and O-16(d,p)O-17* respectively, and the results correlated with the thickness of the carbonaceous layers.