Low-temperature MOCVD of molybdenum sulfide on silicon and 100Cr6 steel substrates

Abstract

Thin films of molybdenum sulfides, MoSx (1<x<2), have been grown on silicon and 100Cr6 steel substrates, in the 130°C-180°C temperature range, using Mo(CO)6and H2S as precursors. Influences of molar fraction, temperature and total pressure on growth rate and chemical and structural features of the layers were investigated. The films are homogeneous and amorphous. The S/Mo ratio depends upon the molar fraction ratio [χH2S/χMo(CO)6], as well as on total pressure and growth temperature. The highest S/Mo ratios were obtained for T = 130°C, P = 3330 Pa and [χH2S/χMo(CO)6] = 150. Friction tests have been carried out at different loads and humidity ratios. The results show that friction coefficient decreases when humidity level decreases : in dry conditions (<5% humidity) the friction coefficient is lower than 0.05. There is also an inverse dependence on the load. In addition, friction tests also show that the films grown by MOCVD have the same hardness and exhibit the same behaviour as films grown by PVD