Residual gas analysis of a dc plasma for carbon nanofiber growth

We report the analysis of a plasma enhanced chemical vapor deposition process for carbon nanofiber growth. A direct current (dc) plasma is employed with a mixture of acetylene and ammonia. Residual gas analysis is performed on the downstream plasma effluent to determine degrees of precursor dissociation and high molecular weight species formation. Results are correlated to growth quality obtained in the plasma as a function of dc voltage∕power, gas mixture, and pressure. Behaviors in plasma chemistry are understood through application of a zero-dimensional model.