Properties of TiN films deposited at low temperature in a new plasma-based deposition system

Stoichiometric titanium nitride (TiN) films were deposited at less than 130 °C in a new configuration of the helicon activated reactive evaporation system. An in situ ellipsometer was used to monitor the optical properties of the films during growth. The film stress, lattice parameter, surface roughness, crystallite size, and preferred orientation were investigated as a function of substrate bias and hence ion energy of the incident species. The intrinsic stress dependence on ion energy shows the expected result also shown by a variety of materials and is in good agreement with the theoretical model of Davis [Thin Solid Films 226, 30 (1993)]. The high stress level at −50 V bias is confirmed by measurement of lattice parameter. X-ray-diffraction measurements show that the (111)-preferred orientation normal to the substrate surface correlates strongly with the stress level of the films. By correlating our results with those from a number of other reported studies at higher substrate temperature we conclude that the observed preferred orientation in TiN films can be explained from the viewpoint of the energy minimization principle. Kinetic factors are of less importance except possibly at the highest bombardment energies.