Growth and characterization of Sc₂O₃ doped Ta₂O₅ thin films

We present the optical and structural characterization of films of Ta₂O₅, Sc₂O₃, and Sc₂O₃ doped Ta₂O₅ with a cation ratio around 0.1 grown by reactive sputtering. The addition of Sc₂O₃ as a dopant induces the formation of tantalum suboxide due to the "oxygen getter" property of scandium. The presence of tantalum suboxide greatly affects the optical properties of the coating, resulting in higher absorption loss at λ=1064nm. The refractive index and optical band gap of the mixed film do not correspond to those of a mixture of Ta₂O₅ and Sc₂O₃, given the profound structural modifications induced by the dopant.