Plasma enhanced chemical vapor deposition of functional coatings using metal-organic compounds

Metal nitrides such as titanium nitride and zirconium nitride are useful materials for industrial thin film functional coatings due to their high hardness, chemical stability, and color resemblance to gold or brass. To perform metal nitride thin film deposition, a new electron cyclotron resonance plasma enhanced chemical vapor deposition (ECR PECVD) system was designed and constructed. This low pressure high density plasma reactor has been used to develop low temperature metal nitride thin film PECVD processes, using statistical design-of-experiment methodology.; Metal-organic compound precursors were used to explore metal nitride thin film deposition with titanium isopropoxide as a precursor for titanium nitride (TiN) deposition and zirconium 2-methyl-2-butoxide and zirconium t-butoxide as precursors for zirconium nitride (ZrN) deposition. Nitrogen (N₂) or ammonia (NH₃) was used as an additive gas and argon (Ar) or helium (He) was introduced as a carrier gas. The effects on metal nitride deposition using nitrogen vs. ammonia and argon vs. helium were compared. Experimental results show that ammonia is the better nitrogen source and argon introduces more effective ion bombardment.; Low temperature deposition has been achieved. Hard and gold-colored metallic-like titanium nitride and zirconium nitride thin film coatings were deposited on stainless steel substrates at temperatures below 250°C for titanium nitride and below 300°C for zirconium nitride. Generally, the substrate deposition temperature increased with increasing input microwave power.; The coating films were characterized using X-ray photoelectron spectroscopy (XPS) for chemical composition analysis and nano-indentation for hardness measurements. XPS analysis revealed that the film composition was strongly influenced by input microwave power as well as flow ratio of additive gas to precursor vapor. Hardness measurements showed that hard films were obtained, with film hardness reaching 60% of the standard TiN hardness for titanium nitride and 80% of the standard ZrN hardness for zirconium nitride.