MoS(x) lubricating thin films were deposited by nonreactive, reactive,
and low energy ion-assisted radio-frequency (rf) magnetron sputtering
from a MoS2 target. Depending on the total and reactive gas pressures,
the film composition ranges between MoS0.7 and MoS2.8. A low working
pressure was found to have effects similar to those of low-energy ion
irradiation. Films deposited at high pressure have (002) planes
preferentially perpendicular to the substrate, whereas films deposited
at low pressure or under low-energy ion irradiation have (002) mainly
parallel to it. Parallel films are sulfur deficient (MoS1.2-1.4). Their
growth is explained in terms of an increased reactivity of the basal
surfaces, itself a consequence of the creation of surface defects due to
ion irradiation. The films exhibit a lubricating character for all
compositions above MoS1.2. The longest lifetime in ball-on-disk wear
test was found for MoS1.5.