| In this study, β-SiC films were prepared on Si (100) substrate by Hot FilamentChemical Vapor Deposition (HFCVD or Cat-CVD) at substrate temperature of300-500oC using CH4, SiH4 and H2. The effects of deposition parameters on thestructure, composition and growth rate of β-SiC films are studied. Experimentresults indicate that the crystallinity and growth rate of β-SiC films are mainlyinfluenced by SiH4 fluxes while slightly by CH4. Appropriate negative and positivebias all can improve the crystallinity of β-SiC films, and the crystal size can beincreased accordingly, whereas too high negative bias can limit the β-SiC crystalsgrowth due to the strong bombardment of ions. For the first time, it is found that theoxygen contamination and amorphous SiC in the β-SiC films can be reduced byaddition of CF4 into precursor gases of CH4+SiH4+H2, thus the crystallinity of β-SiCfilms can be improved evidently. Using precursor gases of CH4+SiH4+H2 and CF4+SiH4+H2, β-SiC films wereprepared by Plasma Enhanced Chemical Vapor Deposition (PECVD) at temperatureof 500-700oC under RF-power of 100-200W. Measurement results indicate that theorder degree of the Si-C bonds prepared using CF4+SiH4+H2 is superior to that ofprepared using CH4+SiH4+H2 under the same experiment conditions. Electrical characteristics of β-SiC films were studied. The measurement resultsof field emission characteristics of β-SiC films indicate that the field emissioncharacteristics of nanocrystalline β-SiC films is superior to that of amorphous SiCfilms, and the field emission characteristics can be improved by decreasing the β-SiCcrystal size. The effects of crystal size on field emission characteristics areanalyzed. Aligned carbon nanotubes (ACNTs) were synthesized by HFCVD in N2 andglow discharge environment. The effects of N2 and glow discharge on the growth ofACNTs are analyzed based on the solution and plasma theory, and the formationmechanism of bamboo like CNTs synthesized in N2 environment is discussed.
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