Volkmar Sottke

Chemical vapour deposition of MoS2 coatings using the precursors MoCl5 and H2S

MoS 2 lubricant coatings were synthesized by low-pressure chemical vapour deposition (LPCVD) using a gas mixture of MoCl 5 , H 2 S and argon. A thermodynamic analysis shows that the deposition of pure MoS 2 can be expected over a wide range of temperatures. Deposition experiments were performed using cemented carbide and silicon substrates. The influence of process parameters on the deposition rate, layer composition and structure of the molybdenum sulphide coatings was investigated. Pure MoS 2 layers can be prepared at substrate temperatures of 500 and 600°C. The chlorine content increases remarkably with decreasing substrate temperature due to the codeposition of ternary MoS x Cl y compounds. At a low n 0 (H 2 S)/n 0 (MoCl 5 ) ratio in the input gas, Mo 2 S 3 is codeposited. Layers deposited at 300°C are amorphous. Between 400 and 600°C, crystalline layers of a different morphology and texture were obtained. TEM investigations show that a preferred orientation of the (002) basal planes exists only for the first range of MoS 2 film growth.