提拉法SiO2化学膜厚度与折射率的变化规律研究

采用提拉法在硅基底上制备了多孔溶胶凝胶SiO2膜，用椭偏法测量薄膜的厚度与折射率，考察了提拉速度和胶体浓度对膜层厚度与折射率的影响。对厚度与提拉速度的关系进行线性与幂函数拟合，并比较分析两种拟合的关系及其对工艺流程的作用。比较了不同浓度胶体所得到的同一厚度薄膜的折射率变化规律。结果表明：对于同一胶体浓度下薄膜厚度与提拉速度的正相关关系，线性拟合相比幂函数拟合可以更好地解释实验结果的规律性。同时，折射率在一定范围内也会随着提拉速度的增加而减小。镀同一厚度膜时，浓度大的胶体膜层折射率大。通过对提拉速度和胶体浓度的控制可以得到理想的薄膜厚度与折射率。

Changes of thickness and refractive index of silica sol-gel film by dip coating process

The porous sol-gel silica film was prepared on silicon substrate by the dip coating process. Coating thickness and refractive index were measured by ellipsometry method. Influence of withdrawal speed and concentration of silica was investigated for the thickness and refractive index of silica. The relation of the thickness and withdrawal speed was fitted by the linear and power functions, and the results were analyzed and compared. It was found that the film thickness increased with the withdrawal speed for the same colloid concentration. Linear relation between film thickness and withdrawal speed was better than power function relation for describing the experiment data. The refractive index of the film decreased with the withdrawal speed. For the same thickness, the refractive index of the film increased with the concentration of silica. The experimental results indicated that the thickness and refractive index of the film can be controlled by changing the withdrawal speed and concentration of silica.