CN distribution in flame deposition of diamond and its relation to the growth rate, morphology, and nitrogen incorporation of the diamond layer

摘要

Two-dimensional laser-induced fluorescence (2D-LIF) measurements are applied to the chemicalvapour deposition (CVD) of diamond by an oxyacetylene flame to visualize the distribution of CN inthe gas phase during the diamond growth process. The obtained diamond deposits are characterizedby optical as well as scanning electron microscopy (SEM) and cathodoluminescence topography(CL). Experiments are carried out in both laminar and turbulent flames and show CN to be presentmostly at the outer edge of the flame, where ambient air interacts with flame gases. Clear relationsare observed between the distribution of CN and the local variation of the growth rate, themorphology, and the nitrogen incorporation as identified by CL in the deposited diamond layer. Theobserved differences between the laminar and turbulent flame can be attributed to enhanced diffusionof nitrogen into the latter. Significant differences are found between the results of experimentsperformed with acetylene gas bottles from two different suppliers.