The role of nitrogen in the deposition of polycrystalline diamond films

Abstract

Abstract The role of nitrogen in the formation of polycrystalline diamond films prepared using a microwave plasma CVD system has been studied using micro-Raman spectroscopy, X-ray diffraction and X-ray photoelectron spectroscopy (XPS). Although the nitrogen concentration in the films was too low to be detected by XPS, the Raman spectrum was found to be significantly affected by the nitrogen flow ratio. The intensity of the Raman peak at 1480 cm−1 significantly decreases, whereas that of 1190 cm−1 peak remains almost unchanged in comparison with the 1350 and 1550 cm−1 peaks with increasing nitrogen flow ratio. In contrast, the preferentially (111)-orientated growth and the growth rate were little influenced by the nitrogen flow ratio. These results indicate that nitrogen plays a special role in the formation and structure of the polycrystalline diamond films studied in this report.