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.