TiO_2薄膜表面粗糙度对光学特性的影响

Surface Roughness and Optical Constant of TiO_2 Thin Film

薄膜表面粗糙度是影响薄膜光学性能的一个重要指标,采用Taylor Hobson表面轮廓仪对离子束辅助电子束热蒸发沉积的二氧化钛(TiO2)薄膜表面粗糙度进行了研究.采用椭偏仪通过选择不同的结构模型研究了不同基底粗糙度上沉积的TiO2薄膜的折射率和消光系数.研究结果表明:0.3 nm/s的沉积速率获得的TiO2薄膜表面粗糙度较小;在基底粗糙度较小时,TiO2薄膜具有一定的平滑作用.通过减小基底的粗糙度和考虑混合模型,TiO2薄膜特性有一定的提升,随着薄膜表面粗糙度的增加其折射率趋于2.08,消光系数趋于0.04.

Surface roughness of thin film is an important indicator affect the optical properties of thin films. The surface roughness of TiO2 thin film with different thickness of substrate roughness are researched by Taylor Honbson coherence correlation interferometer （Talysurf CCI）. The refractive index and extinction coefficient of TiO2 thin film deposited on different roughness substrate are studied by ellipsometer using different model. The experimental results show that the surface roughness of TiO2 thin film is small when the deposition rate is 0. 3nm/s. TiO2 thin film can smooth the substrate roughness when substrate roughness is small. The refractive index of TiO2 thin film increases and extinction coefficient decreases with substrate roughness increase when the roughness layer and mixed layer are not taken into accounted. By reducing the substrate roughness and consideration of mixed model, optical properties of TiO2 thin film are improved.