离子束辅助沉积TiO_2薄膜近红外光学特性分析

Analysis of Optical Constant in Near Infrared Region of TiO_2 Thin Film Deposited by Ion Beam Assisted Deposition

二氧化钛(TiO2)作为一种常用的薄膜材料,对其近红外波段光学特性的研究很少.利用正交试验法,采用椭圆仪对TiO2薄膜近红外波段的光学特性进行了研究.着重研究了薄膜沉积速率、基片烘烤温度和氧气分压等因素对TiO2薄膜近红外波段的折射率和消光系数的影响.实验结果表明,对TiO2薄膜折射率影响最大的两种因素是薄膜沉积速率和烘烤温度.随着沉积速率的增加,薄膜折射率先增加后减小,最佳沉积速率为0.4 nm/s左右;随着基片温度的增加,薄膜折射率从2.15增加到2.23左右;氧气分压也是影响薄膜折射率的主要因素之一,结果表明氧气流量为4.0 sccm(工作真空度1.4×10-2Pa)时折射率最大.该研究为扩宽TiO2薄膜在近红外波段的应用提供了依据.

TiO2 thin film is widely used in optical thin film, but the study on optical constant in near infrared region is very few. The orthogonal test is used in TiO2 film deposition. The refractive index and extinction coefficient of TiO2 film as a function of deposition rate, substrate temperature and oxygen flow are studied by ellipsometer. The experimental results show that deposition rate and substrate temperature strongly influence refractive index of TiO2 film. With the increase of deposition rate, the refractive index of TiO2 thin film increased firstly and then decreased. The best deposition rate is 0. 4nm/s. With the increase of substrate temperature, the refractive index of TiO2 thin film increased from 2. 15 to 2.33. Furthermore, the working press is one of factors effeeting refractive index of TiO2 thin film. The maximum refractive index is got when oxygen flow is in 4. 0 sccm.