Room-temperature growth of high-purity titanium nitride by laser ablation of titanium in a nitrogen atmosphere

Thin films of titanium nitride (TiN) were deposited on glass substrates by KrF excimer laser ablation of titanium over a very broad nitrogen pressure range with different target-substrate distances at room temperature. The as-deposited TiN thin films were analyzed by X-ray diffraction and transmission electron microscopy. It was found that the as-deposited thin films are normally a mixture of TiN and metallic titanium, and the TiN-to-Ti ratio of the as-deposited thin film depends on both the nitrogen pressure and the target-substrate distance. High-purity TiN thin films can be obtained only in a very narrow deposition parameter range. A compound parameter (the product of the nitrogen pressure and the target-substrate distance) is proposed to optimize the deposition of high-purity TiN thin films, and the possible mechanism is also discussed. It was also revealed that the as-deposited TiN thin films are polycrystalline with an average grain size of about 20 nm.