EVIDENCE OF HEXAGONAL DIAMOND IN PLASMA-DEPOSITED CARBON-FILMS

Hexagonal diamond grains of similar to 30 nm diameter together with gr aphite and SiC are seen in predominantly amorphous carbon films deposi ted at low temperature on Si substrates from a CH4 plasma vapour sourc e. The different crystalline phases are identified by grazing-angle X- ray diffraction which allows for substrate rotation and tilting to ena ble the 2 theta peaks to be. correlated with the angular displacements of specific planes. Electron energy-loss spectroscopy shows the chemi cal composition of the films to be predominantly carbon with traces of oxygen. Raman spectroscopy shows the peaks to be associated with amor phous carbon and graphite, together with a peak at 1170 cm(-1) which i s attributed to microcrystalline hexagonal diamond.