Texture of Polycrystalline MoS_x Thin Films Magnetron Sputtered from a Metallic Target in Ar-H₂S Atmospheres

Abstract

The textured film growth of polycrystalline MoS_x films on Si substrates deposited by reactive magnetron sputtering with H₂S from a molybdenum target has been investigated. Over a wide range of gas flow ratios F_H2S/(F_H2S+F_Ar) from 1% to 75% only x-ray diffraction patterns of randomly stacked S-Mo-S layers of the MoS₂ phase were detected which indicates turbostratic growth of the van-der-Waals layers comparable to the growth of graphite at low temperatures. The extended distance of the c-lattice planes depends on the sputtering conditions and can also be explained by the turbostratic model. Low deposition rates and high substrate temperatures improved the quality of the films towards the requested (001) texture and low c-lattice strain. The results from the in situ-energy dispersive x-ray diffraction (EDXRD) technique using synchrotron radiation allowed kinetic calculations of the time dependent behaviour of the peak area of the (0 0 21) Bragg reflection signals according to the Johnson-Mehl-Avrami model. They revealed that the grain growth is restricted in dimensions if a completed nucleation is assumed.