Titanium nitride (TiN) thin films were deposited on Si (100) substrate by direct current reactive sputtering without and with the application of a substrate bias. The aim of this work was to clarify the effects of substrate bias on film properties systematically. The results showed that the substrate bias process changed the film growth regime, and therefore, the stoichiometry, crystalline orientation and morphology were completely different from those of the films prepared without a substrate bias. Importantly, the application of substrate bias contributed a reduction in the resistivity from 100 to 31cm, an increase in density by 12% and a decrease in RMS roughness to less than 1nm. In addition, a significant reduction in leakage current density was observed for capacitors using TiN top electrode deposited with substrate bias.