偏振光反射法测量薄膜参数

Polarized Light Reflection Method for Measuring Thin Film Parameters

根据偏振光反射原理和多角度测量的多点拟合算法,研究了薄膜材料的厚度、实际测量中的噪声、特殊入射角三个因素对薄膜参数测量精度的影响。对SiO2薄膜样品进行数值模拟分析,结果表明,薄膜厚度大于150nm时的反演误差较小,50nm以下的薄膜反演误差较大;噪声越小测量精度越高;SiO2薄膜存在特殊的入射角,该角选为初始入射角将出现较大误差甚至错误,测量时应避开。若初始入射角的选取偏离特殊角±2°,即可消除特殊点所带来的影响。

Based on the principle of reflection of polarized light and measurement of multi-angle multi-fitting algorithm, the influences of the film thickness of the material, the noise factor in actual measurement and the special angle of incidence on the measurement accuracy of film parameters are studied. Numerical simulation of SiO2 thin film sample analysis shows that the inversion error is smaller when the film thickness is greater than 150 nm, while it is large for film thickness below 50 nm; the smaller the noise the higher the measurement accuracy; there is a special angle of incidence for SiO2 films large error even wrong result will be generated if the initial angle of incidence is set at this special value. Selecting the initial angle of incidence to deviate from the special angle by ±2° can eliminate the impact of special points.