WS 2 thin films by metal organic chemical vapor deposition

Abstract

The metal organic chemical vapor deposition (MOCVD) of WS 2 by reaction of H 2S with W(CO) 6 was determined to be thermodynamically favored over a wide range of deposition conditions. Various degrees of crystalline WS 2 films were obtained on Si(1 0 0), and the crystalline orientation, structure and morphology of WS 2 thin films in relation to the deposition conditions were studied. Microstructure for MOCVD-grown WS 2 thin films is generally characterized by the formation of crystallites with basal planes parallel to the interface ( c(=)) for the first few tens of nanometers, followed by the formation of crystallites with their basal planes nonparallel to the substrate ( c(‖)). Formation of the c(=)–WS 2, and transition of the microstructure from c(=) to c(‖) were studied in detail by X-ray diffraction, transmission electron microscopy and atomic force microscopy. Effects of the preferred orientation on the overall crystallinity of thin films and the state of stress were also investigated by Raman spectroscopy.