电子束蒸发SiO_2薄膜残余应力在不同湿度环境下的对比

Contrastive investigation of the residual stress of SiO_2 films prepared by electron beam evaporation in different relative humidity environments

采用电子束蒸发方法在BK7基底上制备SiO2单层膜,通过台式探针轮廓仪分别测量了大气(45%RH)和干燥环境(5%RH)中不同沉积温度下制备的SiO2单层膜残余应力,同时使用分光光度计和原子力显微镜对样品的折射率和表面形貌进行研究。测试结果表明:SiO2薄膜的残余应力在两个环境中均表现为压应力,且随沉积温度的升高均逐渐增大。干燥环境下与大气环境相比,应力值减小了约100MPa。此外,随沉积温度的升高,薄膜折射率不断增大,表面粗糙度逐渐减小。说明:随着沉积温度的变化,SiO2薄膜的微结构发生了改变。相应地,由水诱发的应力随薄膜致密度的增加而逐渐减小。

Silicon dioxide films were deposited on BK7 substrates under different deposition temperatures using electron beam evaporation method.The residual stresses in SiO2 films were measured in clean-room（45% humidity） and dry Nitrogen environments（5% humidity） by a stylus profiler separately.Moreover,the refractive indices and microstructure of the SiO2 films were characterized using spectrophotometer and atomic force microscope.The observations suggest that all of the SiO2 films exhibit compressive stress in both environments,and the compressive stress increases with the rise of deposition temperature.Compared with the dry Nitrogen environments,the value of stresses decrease about 100 MPa in clean-room.Increase the deposition temperature,the microstructure become dense concluding from the high refractive indices and the low surface roughness.Accordingly,the stress induced by water decreases when the microstructure of films become denser.