Raman scattering of nitrogen incorporated diamond thin films grown by hot filament chemical vapor deposition

A detailed Raman scattering analysis of nitrogen incorporated polycrystalline diamond thin films grown using NH3/CH4/H2 gas mixture in hot filament chemical vapor deposition system is presented. To understand the nitrogen bonding configuration in these films, diamond films are grown by replacing H2 with D2 in the gas mixture. The Raman peak observed at ~1190 cm−1 showed an isotopic shift to ~830 cm−1 upon replacing H2 with D2 in the gas mixture. With the present Raman analysis, the peak at ~1190 cm−1 is assigned to CNH. Secondary ion mass spectroscopy revealed the abundance of nitrogen in the sub-surface region of the annealed diamond thin films.