OPTIMIZATION OF THE PLASMA-CVD PROCESS FOR HARD COATINGS BY MEANS OF OPTICAL-EMISSION SPECTROSCOPY

The deposition of titanium nitride layers by pulsed-DC-PA-CVD was inve stigated by optical emission spectroscopy Ti+ and N2+ were controlling factors for layer growth. An occurrence of TiN in the gas phase for h igher plasma power deteriorates the layer properties, such as hardness . The analysis of the chemical composition of the layers shows a contr ary behaviour of nitrogen and chlorine. The chlorine content affects t he hardness of the layers. Chlorine was detected in the discharge in a tomic form. No titanium chlorides could be detected. The morphology of the crystal growth is dependent on the deposition parameters.