基于透射光谱的类金刚石膜光学参数反演

Calculation of Optical Parameters of Diamond-like Carbon Film Based on Transmission Spectrum

本文采用透射光谱法测量Ge基底类金刚石薄膜(Diamond-like carbon,DLC)的光谱曲线。应用测量的光谱曲线,基于模拟退火算法,构建目标优化函数,通过光谱反演法得到薄膜的厚度、折射率、消光系数。该方法得到的Ge基底类金刚石膜的光学参数与椭偏仪测试结果比对,折射率误差小于1%,厚度误差小于2%。并且将薄膜的光学参数带入透过率理论计算模型,得到的Ge基底类金刚石薄膜透射光谱曲线和实际测试曲线的误差小于2%。该方法只需测量透射光谱曲线,通过计算就能得到薄膜光学参数,对光学薄膜设计和加工具有重要指导意义。

In this paper,transmission spectroscopy was used to measure the spectral curve of Diamond-like carbon film on Ge substrate.By using the measured spectral curve and simulated annealing algorithm,the objective optimization function was constructed,and the thickness,refractive index and extinction coefficient of the film are obtained by spectral inversion.Compared the optical parameters of Diamond-like carbon film on Ge substrate obtained by this method with the measured results of ellipsometer,the error of refractive index is less than 1%,the error of thickness is less than 2%.In addition,the optical parameters of the film were brought into the theoretical calculation model of transmittance.Compared with the actual measured curve,the error of the transmission spectrum curve of Diamond-like carbon film on Ge substrate is less than 2%.Once the transmission curve measured,the optical parameters of the film can be obtained by calculation.