Microwave diamond synthesis with high oxygen hydrocarbons-(carbon dioxide, oxygen)

Autor: Sheng-Hsiung Chen, Chia-Fu Chen, S.E. Sheu, Hsien-Wen Ko, Tsao-Ming Hong
Rok vydání: 1993
Předmět:
Zdroj: Thin Solid Films. 236:120-124
ISSN: 0040-6090
DOI: 10.1016/0040-6090(93)90655-9
Popis: Our previous study demonstrated that a higher growth rate and improved crystallinity resulted from using CH4CO2 mixtures in diamond deposition. The possibility of diamond synthesis using a high oxygen-containing liquid hydrocarbon, dimethyl carbonate (C3H6O3), supplemented by CO2 or O2 was therefore explored in the present study. Well-faceted diamond was deposited when the ratios of the respective flow rates for CO2/C3H6O3 and O2/C3H6O3 were 6%–8% and 1.5%–2.25%. The growth rates of the diamond films, which were of high quality, were 3.6 and 1.7 μm h−1 respectively. The diamond films displayed different surface morphology and crystal features in these gas mixtures, i.e. the diamond film possessed more (311) and (100) facets in the O2C3H6O3 mixture at a power of 400 W. The diamond film deposited from 6.75% CO2 in C3H6O3 was indicated by the roughness determination not only to possess a higher growth rate but also to attain a smooth surface with a roughness of 0.048 μm (Ra). The surface roughness of the diamond film was 0.083 μm for 2% O2 in C3H6O3. The intensities of CO, OH and O produced from O2C3H6O3 mixtures were observed by optical emission spectroscopy measurements to be greater than those produced from CO2C3H6O3 mixtures, but the intensities of C2 and CH showed the opposite trend. This was the main difference between the CO2C3H6O3 and O2C3H6O3 mixtures. Therefore a larger amount of etching agents appears to block the nucleation of diamond in O2C3H6O3 mixtures. The complete results of our study, including Raman and X-ray diffraction analyses, are presented here.
Databáze: OpenAIRE
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