Residual stress and optical properties in a post-annealed Ta ₂O ₅/SiO ₂ multilayer prepared by using dual-ion-beam sputtering

The residual stress and optical properties of Ta ₂O ₅(H)/SiO ₂(L) single and multilayers were examined as functions of the annealing temperature (200-400°C) using dual ion beam sputtering (DIBS). The residual stress of the annealed SiO ₂, Ta ₂O ₅ single layer was released, and all were found to be in compressive stress when the annealing temperature ranged from 200 to 300°C. The residual stress of the as-deposited (HL) multilayer film increased as the number of layers increased. The residual stress of the (HL) ³ and the (HL) ⁴ films was released as the annealing temperature was increased. The transmittance wavelength of the (HL) ⁴ layer shifted to a longer wavelength as the temperature was increased and the rms roughness increased.