Nitrogen compounds and their influence on diamond deposition in flames
Abstract
The influence of nitrogen-containing species on the growth of diamond films is well-established in microwave and hot filament chemical vapour deposition (CVD) systems. Here, diamond CVD was investigated in atmospheric acetylene–oxygen flames doped with N-containing species [N2, N2O, NH3, N(CH3)3]. Small amounts of these additives increase the growth rate, while higher concentrations lead to preferential s carbon deposition. The growth-effective amount of N-additive decreases by more than an order of magnitude in the sequence N2>N(CH3)3N2O>NH3. Simulation of the gas phase chemistry in a stagnation-flow geometry shows that the transformation of the additives towards HCN, NO and N is strongly correlated with growth enhancement and film quality decrease.