Biased enhanced nucleation of diamond on metals: An OES and electrical investigation

Biased enhanced nucleation (BEN) on non-diamond substrates is poorly understood and displays problems of reproducibility. In this work, optical emission spectroscopy (OES) and electrical measurements have been used to study the BEN process. OES reveal changes in the chemical species within the plasma that occur as a result of the applied bias to a tungsten substrate, As the bias is applied the atomic hydrogen intensity and the ratio of C-2 to CH species detected changes considerably. Both effects appear to be greatest near the substrate surface. The results are discussed in terms of possible origins for the bias enhanced nucleation process. Electrical measurements indicate that reactor pressure may be responsible in part for the reproducibility problems often associated with the BEN technique. (C) 1997 Elsevier Science S.A.