Growth, surface morphology, optical properties and electrical resistivity of &#949;-TiN<SUB>x</SUB> (0.4&lt;x≤=0.5) films

The growth, structure, surface morphology, optical properties and electrical resistivity studies on TiN<SUB>x</SUB> (0.4&lt;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<SUB>2</SUB> 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<SUB>2</SUB> 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 &#949;-Ti<SUB>2</SUB>N (3 1 1) with a crystallite size of 60 nm. Surface morphologies varied dramatically with N<SUB>2</SUB> pressure. The electrical resistivity of the film deposited at 12 mTorr was 37 M&#937; cm whereas it is 270 k&#937; cm for the films deposited at 25 mTorr. Therefore, the current work provides signatures for the &#949;-Ti<SUB>2</SUB>N 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