Experimental design and modelling in the investigation of process parameter effects on the tribological and mechanical properties of r.f.-plasma-deposited a-C : H films

Hydrogenated amorphous carbon (a-C:H) films were deposited by the r.f. plas ma technique in order to study the effect of deposition parameters on the m echanical and tribological properties of the films. An experimental design method was used for planning the experiments, and statistical analysis and modelling to analyse the results. The high hardness of the film was found t o have the highest correlation with the good wear resistance of the film. B y using response surface modelling, some direct trends from the process par ameters to tribological properties were found. The best wear resistance for the a-C:H films was found for low pressure (0.7-2.5 Pa) and intermediate b ias voltage (-550V) values. By using the experimental design, the number of deposition runs could be reduced, and the statistical analysis and modelli ng provided useful and precise information showing also the significance of the trends observed. (C) 1999 Elsevier Science S.A. All rights reserved.