Effect of postdeposition annealing on the structure, composition, and the mechanical and optical characteristics of niobium and tantalum oxide films

摘要: Optical, mechanical, and thermal properties of optical thin films are very important for a reliable device performance. In the present work, effect annealing on stability characteristics niobium tantalum oxide grown at room temperature (RT) by dual ion beam sputtering were studied. The refractive index (n(λ)), extinction coefficient (k(λ)), hardness (H), reduced Young’s modulus (Er), film stress (σ) investigated as function (TA). X-ray diffraction analysis showed that all as-deposited amorphous, crystallization was observed only after 700°C. Compositional analyses confirmed atomic ratio oxygen to metal in annealed close 2.5, indicating stoichiometric pentoxides Nb Ta. Nb2O5 Ta2O5 were, respectively, affected postdeposition annealing: n(λ) values (at 550 nm) decreased from 2.30 2.20 2.14 2.08, average H Er increased 5.6 7.4 GPa, 121 132 GPa Nb2O5, 6.5 8.3 GPa, 132 144 GPa Ta2O5, initial low compressive both materials changed tensile. We explain variation coating material terms stoichiometry, crystallinity, electronic structure, possible reactions film–substrate interface.