Growth Parameters Optimization to Synthesize Cvd Diamond through Graphite Etching

Diamond films were deposited from graphite etching as a carbon source with atomic hydrogen instead of using conventional hydrocarbon in the feed gas. A graphite plate was used as sample support in a hot filament chemical vapour deposition reactor. Graphite temperature, gas flow rate as well as the pressure inside the reactor presented a strong influence on the diamond growth rate, morphology and quality. Scanning electron microscopy images showed that the films grown at 600 and 700 oC depicted similar morphologies while the film grain size decreased as a function of the pressure and the gas flux increases. Raman analyses confirmed good diamond quality in the whole ranges of such parameters variation and was also used to analyse the sp/sp ratios of the three produced sample sets. For deposition time of 4 h the process efficiency was evaluated from the ratio between the diamond mass after deposition and the mass lost by the graphite target. In the range of the experimental parameters studied the highest efficiency value was 0.43 obtained at 700 oC, for a pressure of 30 Torr and flux of 100 sccm, respectively.