Deposition of carbon nitride thin films by IR-laser-induced reactions in carbon-nitrogen gas-phase compounds

Since the theoretical studies of Liu and Cohen who predicted the existence of a superhard phase of carbon nitride, a great deal of effort was underdone in order to synthesize this hypothetical material with a nitrogen content as high as the 57% present in a β-C₃N₄ structure. This study presents an attempt to produce CN_x thin films using the laser-induced CVD technique. CW CO₂ laser was used for irradiating various carbon-nitrogen containing mixtures such as C₂H₄/N ₂O/NH₃. The CN_x films were grown alternatively on bare alumina (α-Al₂O₃) substrates and on pre-deposited Ti films. A comparative analysis of nitrogen incorporation in the films obtained in different experimental conditions was performed by means of the X-ray photoelectron spectroscopy (XPS). The same method was used to identify the chemical states of the CN system.