In situ spectroscopic ellipsometry as a sensor for hard coatings and steel nitriding

In this work, where the major emphasis has been given to in situ and on-line measurements, we extend the available experience in the field of spectroscopic ellipsometry to plasma-assisted chemical vapour deposition (PACVD) hard coatings and diffusion layers on steel, namely TiN, TiCN, TiAIN and Fe x N y . Furthermore, Auger electron spectroscopy was carried out in order to correlate the spectroscopic ellipsometry data on an absolute scale to their composition. It could be shown that monitoring of whole standard industrial processes (up to 24 h) for the control of nitriding/deposition processes is easily achievable. Thus, the formation of compound layers, the effectiveness of sputtering and the nitriding process as well as the composition of hard coatings (TiN and compounds) can be determined in real time in order to control and tune on-line the fabrication of PACVD hard coatings.