Heat treatment of nanocrystalline TiN films deposited by unbalanced magnetron sputtering

Abstract

TiN thin films were deposited on Si wafers using an unbalanced magnetron (UBM) sputtering technique. Heat treatment was implemented after deposition to improve the properties of the TiN thin films. Combinations of mixing gas atmospheres and Ti getter were evaluated by thermodynamic and kinetic estimations to find a heat treatment environment with minimum oxidation. Results showed that at 700 °C the oxidation of TiN thin film could be minimized under an atmosphere with a partial pressure ratio of Ar/H2=9 and attached with a Ti getter. The specimens were heat-treated at 500 and 700 °C for 1 h under Ar/H2 atmosphere. Heat treatment showed significant effect on the microstructure, crystallinity, texture, grain size, roughness, and residual stress of the nanocrystalline TiN films, while less distinct effect was found on N/Ti ratio, packing factor and electrical resistivity. In addition, the changes in structure and mechanical properties were more effective at 700 °C than those at 500 °C. The changes in texture, grain size, and crystallinity were more obvious in the specimens with a thickness less than 214 nm. The residual stress and hardness were distinctly decreased by the heat treatment especially at 700 °C. This could be attributed to the reduction of lattice defects by the heat treatment.