The structure and composition of rf reactively sputtered MoSx films

Molybdenum sulfide films have been deposited by reactive sputtering of molybdenum in a hydrogen sulfide/argon atmosphere and by sputtering of molybdenum disulfide in pure argon atmosphere at substrate temperatures between room temperature and 480 °C. The structure and composition of the films have been determined as a function of hydrogen sulfide partial pressure and substrate temperature by transmission electron microscopy (TEM) and Rutherford ion backscattering, respectively. The experiments showed that at hydrogen sulfide partial pressures above 2×10−4 Torr, MoSx films had a rhombohedral structure with 0<x<2.2. The dependence of the film thickness on the hydrogen sulfide partial pressure has been studied. The dependence of the composition on the substrate temperature is interpreted by a different dependence of the sticking coefficient of the components on the temperature.