From RTA to conventional annealing: Impact on optical losses and metallic character of TiN films

This study investigates the effects of rapid thermal annealing (RTA) and conventional annealing on the optical and metallic properties of TiN thin films. TiN films were subjected to Au ion implantation, followed by RTA and conventional annealing at 400°C and 500°C for 1 h. Ion implantation led to a decrease in metallicity and optical losses compared to the as-deposited film, with plasma frequency increasing from 6.44 eV to 8.85 eV and Drude broadening from 0.82 eV to 2.43 eV. After RTA, both plasma frequency and Drude broadening were lowered to 4.95 eV and 0.73 eV, respectively, enhancing the metallic character and further minimizing optical losses. Conventional annealing at 400 °C and 500 °C also decreased metallicity but resulted in comparable losses to RTA. However, losses slightly increased at 500 °C due to the growth of Au nanoparticles, which introduced additional scattering mechanisms. These findings demonstrate the importance of thermal treatments in tuning TiN films’ optical and electronic properties, with RTA offering similar results to conventional annealing but with shorter processing times, making it ideal for applications requiring low optical losses and metallic characteristics. © 2025 Elsevier B.V.