The effects of nitrogen flow on the Raman spectra of polycrystalline diamond films

Abstract

The effects of nitrogen on the formation and structure of polycrystalline diamond films prepared using a microwave plasma chemical vapour deposition system have been studied using Raman scattering, X-ray diffraction and X-ray photoelectron spectroscopy. It is found that the Raman spectra are significantly affected by nitrogen flow ratio, while the X-ray diffraction spectra only show certain changes in their peak intensity. Five Raman scattering peaks at 1140, 1190, 1350, 1480 and 1550 cm-1, respectively, are clearly observed. With increasing nitrogen flow ratio, the 1480 cm-1 peak decreases significantly and the 1140 and 1190 cm-1 peaks remain almost unchanged in comparison with the 1350 and 1550 cm-1 peaks. These results indicate that nitrogen plays an important role in modifying the structure of polycrystalline diamond films. © 1998 Published by Elsevier Science Ltd. All rights reserved.