Annealing effects on the properties of TiN thin films

The structure, absorption coefficient and electrical resistivity studies on TiN thin films are presented. The film of thickness 240 nm was grown on Si (100) substrate by DC reactive sputtering at an average deposition rate of ∼8 nm/min. After deposition the samples were annealed for 1 h at 600 °C and 2 h at 700 °C in nitrogen ambient and vacuum furnace, respectively. Structural characterizations were performed by Rutherford backscattering spectrometry (RBS), X-ray diffraction (XRD) and transmission electron microscopy (TEM). The optical properties were investigated by spectroscopic ellipsometry while a four point probe was used for electrical characterization. It was found that the post-deposition annealing of the films did not cause any variation in stoichiometry, but strongly affects the structural parameters such as lattice constant, micro-strain and grain size. The observed increase in the grain size after annealing leads to significantly lower value of the coefficient of absorption. These changes could be directly correlated with variation of electrical properties of TiN thin films