Morphology of TiN coating produced by laser ablation

The morphology of TiN thin films on a steel surface produced by ablation was investigated. The process involves material removal from a titanium target by an ultraviolet excimer pulse laser. Both the target and the steel substrate are in an ammonia atmosphere and therefore the titanium atoms react with the nitrogen under the influence of a laser-induced plasma, and the product, which is TiN, is deposited on the surface of the steel. The investigation revealed that at the beginning of the process the TiN film is uniform; however, with increasing number of pulses, small micrometre-sized particles begin to appear on the surface and after a large number of pulses all the surface is covered with these particles. 17 refs.