Application of optical emission spectra in controlling dominant crystalline surface of diamond films deposited by DC arc plasma jet CVD

Abstract

Dominant crystalline surface of diamond film growth was tried to control by the help of optical emission spectroscopy in situ detection in high power DC arc plasma jet chemical vapor deposition system. The radicals, like CH, C 2, H γ, H 2 and H β, were strongly influenced by the substrate temperature and the concentration of Ar, H 2 and CH 4 in the feed gas. Altering the deposition parameters, the emission intensities of various radicals changed, and the intensity ratio of C 2/H β varied more sensitively than that of CH/H β. The diamond films with excellent (111) dominant crystalline surface were deposited by modifying the radicals atmosphere that had a higher intensity ratio of CH/H β and a lower intensity ratio of C 2/H β, i.e. the intensity ratio of CH/C 2 was higher than 0.41. Very clear columnar crystals shown in the cross-section of the as-grown films indicated the stability of dominant surfaces growth within this atmosphere of radicals. The stable growth was also proven by the results of X-ray diffraction detection vs. deposition time.