Influence of nitrogen addition on oxyacetylene flame chemical vapor deposition of diamond as studied by solid state techniques and gas phase diagnostics

The effect of nitrogen addition on oxyacetylene flame deposition of diamond has been investigated. Two-dimensional laser-induced fluorescence measurements of CN radical distributions in the flame during deposition have been performed. These measurements show that nitrogen added to the source gases and nitrogen from the ambient air dominate the CN formation in the central and outer-flame area, respectively. Both sources of nitrogen have a significant influence in the area between the other two. Most of the observed film morphologies, which were studied by scanning electron microscopy, can be understood from the recently developed deterioration-gradient (DG) model for chemical vapor deposition of diamond, reported by J. J. Schermer et al. [J. Cryst. Growth 243, 302 (2002)]. It was found that the nitrogen range in which the α-parameter, defined by C. Wild et al. [Diamond Relat. Mater. 2, 158 (1993)], changes from slightly below or equal to 1.5 to a value of 3 or more, is extremely narrow. This implies that u...