Growth, surface morphology, optical properties and electrical resistivity of ε-TiNx (0.4 ≤ x ≤ 0.5) films

The growth, structure, surface morphology, optical properties and electrical resistivity studies on TiNx ( 0.4 < x <= 0.5). films is presented. The. films of thickness 116-230 nm were grown on fused silica substrates by RF magnetron sputtering in 100% pure nitrogen atmosphere at ambient temperature and pressures from 12 to 25 mTorr. For the as-deposited. films, the refractive index decreased from 1.86 to 1.6 with increasing N-2 pressure from 12 to 25 mTorr. The absorption edge for the. film deposited at 12 mTorr was 4.7 eV and it decreased to 3.5 eV on increasing the N-2 pressure to 25 mTorr. Post-deposition annealing of the. films at 873 K for 1 min did not cause any variation in the optical properties. The. film deposited at 25 mTorr and annealed at 873 K showed a nanocrystalline peak corresponding to epsilon-Ti2N (3 1 1) with a crystallite size of 60 nm. Surface morphologies varied dramatically with N-2 pressure. The electrical resistivity of the. film deposited at 12 mTorr was 37 M Omega cm whereas it is 270 k Omega cm for the. films deposited at 25 mTorr. Therefore, the current work provides signatures for the epsilon-Ti2N phase in terms of refractive index, optical absorption edge and electrical resistivity, that can be used to identify the presence of the sub-stoichiometric forms in a TiN film. (C) 2008 Elsevier B. V. All rights reserved.