Optical emission spectroscopy on pulsed-DC plasmas used for TiN depositions

The plasma-assisted chemical vapour deposition process in a large-scale industrial plant for coating of TIN on tool steels was investigated by optical emission spectroscopy. Several atomic lines and molecular bands were identified. A parametric study of the dependence of bias voltage, total pressure and gas flows, H-2, N-2, Ar and TiCl4, on the plasma characteristics was performed to gain understanding of the influence of the parameters on the deposition process. With the change of process parameters, large variations in the emitted light, corresponding to changes in plasma conditions, were observed. In the parameter range studied, the deposition rate depends linearly on the N-2(+) signal when varying the pressure and the N-2 flow, whereas no clear correlation between the OES signal and the deposition rate could be found for variations of the other parameters. (C) 1998 Elsevier Science S.A.