Study on the electron cyclotron resonance plasma chemical vapor deposition of carbon nanotubes

In this paper, the carbon nanotubes growth on porous silicon substrates by electron cyclotron resonance plasma chemical vapor deposition (ECR-CVD) method are studied as the function of the flow ratio of CH4/(H2 + CH4), the total pressure in vacuum chamber and the substrate temperature. The results showed that the flow ratio of CH4/(H2 + CH4) and the total pressure are the key factors on the concentration of carbon radical in the chamber, which will influence the growth rate, the density and the orientation of carbon nanotubes. The outer diameters of carbon nanotubes could be controlled by changing the substrate temperatures, it was shown that the aligned carbon nanotubes cannot be formed at lower temperature.