Influence of substrate temperature on structural and optical properties of HfO₂ thin films

HfO2 films were deposited by direct current reactive magnetron sputtering on n-type Si(100) substrates and fused silica substrates, respectively. The substrate temperature ranges from room temperature to 500 ℃. The influence of substrate temperature on structure and optical properties of the films was investigated by X-ray diffraction(XRD), spectroscopic ellipsometry(SE) and ultraviolet visible spectroscopy(UV-vis). XRD results show that all deposited films are polycrystalline with monoclinic structure. As the substrate temperature increases, the preferred orientation of (-111) becomes more obvious, and the grain size of HfO2 films increases. SE and UV-vis results demonstrate that, with the substrate temperature increasing, the refractive index increases and the optical band ga