Synthesis of TiN thin films from titanium imido complexes

Abstract

Thin films have been formed on glass by low pressure chemical vapour deposition from eleven closely related single-source precursors of generic form [TiCl₂(NR)(L)_x] (where x = 1, L = tridentate N-ligand; x = 2, 3, L = monodentate N-ligand). Most of the precursors formed titanium nitride films, however, bulkier imido complexes and those with chelating ligands tended to produce thin films with significant oxygen and carbon contamination, suggesting incomplete decomposition and post reaction oxidation. The best single-source precursor was found to be [TiCl₂(N^tBu)(py)₃], which gave gold-coloured films of stoichiometric TiN_1.0. Despite the coordination environment around the metal being essentially the same and the materials having comparable volatility, significant differences in film quality were observed.