The nucleation and growth of (100) textured diamond films in presence of nitrogen

we have studied the influence of nitrogen addition in CH4/H-2 gas mixtures on the nucleation, morphology and growth rate of polycrystalline diamond fi lms prepared by hot filament chemical vapor deposition (HFCVD). The presenc e of nitrogen has little effect on diamond nucleation density, but is benef icial to enhance the growth rate and to stabilize (100) facets of diamond f ilms. Optical emission spectroscopy was applied to detect the chemical radi cals in the system. it is shown that the additional nitrogen makes the chem ical radicals and surface activity of diamond films change tremendously. We believed that nitrogenous species abstract the atomic hydrogen on the diam ond surface and speed up the desorption rate of H, so as to promote the dia mond films deposition. Furthermore, the selective absorption of nitrogenous species causes chemical roughening of the (100) facets, which makes the gr owth rate of (100) facet higher than that of other facets and leads to the presence of(100) textured diamond films.