The effects of processing parameters in the low-temperature chemical vapor deposition of titanium nitride from tetraiodotitanium

Key findings are presented from a systematic study aimed at establishing a fundamental understanding of precursor decomposition pathways and resulting film nucleation and growth kinetics in the chemical vapor deposition of titanium nitride from tetraiodotitanium. As part of the study, key process parameters were varied systematically in order to determine process activation energy and establish corresponding functionality curves for film purity, growth rate, structure, and morphology. The key process parameters studied were substrate temperature, source temperature, hydrogen carrier gas flow, and reactor pressure. Corresponding findings indicated that all four parameters showed a direct and significant effect on film quality. Additionally, a thorough evaluation of resulting film composition, texture, and electrical properties led to the identification of a wide process window for the growth of TiN films with optimized characteristics and performance. In this process window the TiN films were nitrogen-rich, with iodine concentrations below 2 atom %, displayed resistivities in the range 100 to 150 mu Omega cm, depending on thickness, and exhibited excellent step coverage, better than 90% conformality in both nominal 0.45 mu m, 3:1 aspect ratio and 0.25 mu m, 4:1 aspect ratio contact structures.