Simulation of Gas Phase Chemistry in C-H-O and C-H-N Systems for Chemical Vapor Deposition Diamond Films

Gas phase chemistry in C-H-O and C-H-N systems was simulated. Phase diagrams for chemical vapor deposition diamond films with oxygen-containing and nitrogen-containing feed gases were successfully constructed. The influences of oxygen and nitrogen addition on diamond growth were also discussed. It is shown methyl is the dominant diamond growth precursor, acetylene contributes to non-diamond carbon deposition and atomic hydrogen etches non-diamond carbon. Oxygen addition varies the concentrations of these radicals, which influences diamond growth. Nitrogen addition varies their concentrations as well as produces nitrogen-containing radicals such as CN, which participate in surface chemistry in diamond nucleation and growth.