Influence of N⁺ ions on bandgap and electrical resistivity of TiN thin films

In the present work, nitrogen ions are embedded into Ti thin films (200 nm) using low energy ion beam implantation (70 keV) by varying ions fluence from 4×10¹⁵ ions/cm² to 2×10¹⁶ ions/cm². For this, Ti films were grown using DC magnetron sputtering in Ar environment (power 200 W). TiN films were then characterized using versatile techniques for estimating the band gap and electrical resistivity. X-ray diffraction pattern shows shift in peaks towards higher angle with increase in nitrogen fluence that confirms the introduction of strain in Ti films. UV-Vis spectra show that band gap is reduced from 3.75 eV to 1.7 eV with increase in fluence from 4×10¹⁵ ions/cm² to 2×10¹⁶ ions/cm². Furthermore, electrical resistivity also decreases from 2.67×10⁻⁴ Ω.cm to 2.31×10⁻⁴ Ωcm with nitrogen ion fluence. Based on these results, it can be inferred that ion implantation is an effective approach for uniform distribution of N ions in host matrix and tuning of optical and electrical properties.