ZIRCONIUM CARBONITRIDE FILMS PRODUCED BY PLASMA-ASSISTED METAL-ORGANIC CHEMICAL-VAPOR-DEPOSITION

Zirconium carbonitride thin films were deposited on steel substrates b y means of the d.c. plasma-assisted chemical vapour deposition techniq ue using tetrakis-(methylethylamido)-zirconium (Zr(NMeEt)(4))and tetra kis-(diethylamido)-zirconium(Zr(NEt(2))(4)) as precursors. Depositions were successfully carried out at a substrate temperature of 350 degre es C using the carrier gases hydrogen, nitrogen and argon at a total p ressure of 200 Pa. The influence of the precursors on the deposition r ate and film morphology was studied by scanning electron microscopy. B y means of X-ray diffraction and X-ray photoelectron spectroscopy (XPS ) it was established that f.c.c. Zr(C,N) coatings were obtained which contain a significant amount of oxygen and organic bonded carbon. Usin g Zr(NEt(2))(4) as the starting source, the substrate temperature was varied from 200 to 500 degrees C. The deposition rate, morphology and chemical composition of the coatings depend on the substrate temperatu re. Up to a temperature of 400 degrees C, fine-grained polycrystalline Zr(C,N) coatings were obtained. If the substrate temperature was kept below 300 degrees C, the morphology of these coatings exhibited a col umnar structure. XPS measurements revealed that the amount of organic bonded carbon impurities in the films decreased at deposition temperat ures above 250 degrees C. The Vickers hardness of the coatings deposit ed at 300 degrees C at maximum growth rate reached 2000 HV.