CHARACTERIZATION OF TANTALUM IMPURITIES IN HOT-FILAMENT DIAMOND LAYERS

During hot-filament diamond deposition metal impurities (e.g. tantalum ) can evaporate from the filament. The incorporation of tantalum in di amond films was studied as a function of process conditions using seco ndary ion mass spectrometry, Rutherford backscattering spectrometry an d transmission electron microscopy. It was found that the tantalum con centration depends on the initial carburization status of the filament , its temperature and the diamond growth rate. If diamond deposition i s started with metallic tantalum filaments, TaC nanoprecipitates are f ormed at the interface.