Composition of Ti-C:H films obtained by pulsed and continuous magnetron sputtering

Abstract

The Ti-C:H films have been prepared by reactive pulsed and continuous DC magnetron sputtering of the Ti target in a gas mixture of Ar and CH4. The influence of pulsed and continuous discharge power on the film composition has been studied. For continuous sputtering, the discharge power was 300, 950 and 2850 W. At pulsed sputtering, the average discharge power was about 950 W in most depositions, while pulse power was varied from 2850 to 13000 W.The composition of the obtained films depended very strongly on the power for continuous discharge and only slightly on the pulse power at constant average power. In the latter case the film composition depended on pulse duration, CH4/Ar ratio and, in general, did not coincide with that obtained by continuous sputtering at the same power. The increase of discharge power at continuous sputtering led to reactive gas pressure decrease and to enrichment of the films with metal component. In contrast, the high level of pulsed discharge power cannot decrease considerably the reactive gas pressure during short pulse-on time followed by relatively long pulse-off time so that the film composition cannot be changed significantly as in the case of continuous reactive sputtering. It was supported by optical emission measurements.