Plasma reaction of group VI metal carbonyls

The hexacarbonyl compounds of Cr, Mo, and W have been used as precursors in plasma-enhanced chemical vapor depositions (PECVD). They form films of good adherence on glass, ceramics, and a variety of polymers. The nature of the deposits depends very much on the composition of the gas, which forms the plasma. When pure argon is used, the resulting films contain considerable amounts of oxygen and carbon. Films deposited in hydrogen/argon mixtures consist of the metal and/or the carbide. With Ar/O₂ mixtures, Mo(CO)₆ and W(CO)₆ are converted into films of MoO₃ and WO₃, respectively. When H₂S/H₂ mixtures are used as plasma gas, Mo(CO)₆ yields films consisting of MoS_x.