Effects of different process parameters on the properties of carbon films prepared by thermal chemical vapor deposition using ethylene and nitrogen

• Main Authors: Ke-Jie Huang, 黃柯傑
• Other Authors: 薛顯宗
• Format: Others
• Language: zh-TW
• Published: 2011
• Online Access: http://ndltd.ncl.edu.tw/handle/93977228247375375884

碩士 === 國立中興大學 === 材料科學與工程學系所 === 99 === This study investigates the effects of different ethylene/nitrogen ratio, deposition temperature, working pressure, and mass flow rate on the properties of carbon films prepared by thermal chemical vapor deposition. In addition, this study also considers the influences of different ethylene/nitrogen ratio on the characteristics of carbon coatings on optical fibers. The C2H4/(C2H4+N2) ratios, deposition temperatures, working pressures, mass flow rates, and deposition time were set to 60 ~ 100 %, 1013 ~ 1053 K, 23 ~ 67 kPa, 20 ~ 100 sccm, and 30 min, respectively. The thin film thickness, microstructure, surface roughness, surface property, electrical property, and low-temperature morphology of carbon films were investigated by alpha step, field emission scanning electron microscopy, X-ray diffraction spectrometer, Raman scattering spectrometer, X-ray photoelectron spectrometer, atomic force microscopy, contact angle meter, four-points probe, and optical microscopy. The results indicate that the deposition rate increases as the C2H4/(C2H4+N2) ratio, deposition temperature, and working pressure increase, but the deposition rate increases as the mass flow rate decreases. The deposition rate is proportional to about second-order and third-order of partial pressure of ethylene. The ordered degree, nano-crystallite size (La and Lc), and sp2 carbon atoms decrease as the C2H4/(C2H4+N2) ratio increases. The results also show that the surface roughness decreases as the C2H4/(C2H4+N2) ratio increases from 60 to 80 %, whereas increases as the C2H4/(C2H4+N2) ratio from 80 to 100 %. Alternatively, the water contact angle shows an opposite trend with respect to the surface roughness. As the C2H4/(C2H4+N2) ratio increases, the electrical resistivity of carbon films increases. Finally, based on the low-temperature morphology of carbon coatings, it is good for producing hermetic optical fiber coatings with the carbon thin thickness exceeding 149 nm.