由于光学薄膜的透射光谱和反射光谱受表面粗糙程度的影响很大，因此在确定表面粗糙薄膜的厚度及光学常量时，如果不考虑这种影响必然会引起较大的误差。利用标量波散射理论，引入表面均方根粗糙系数，对粗糙薄膜表面的光散射进行了细致分析，得出了光散射影响下薄膜系统透射系数的表达式。在此基础上计算的薄膜厚度以及透射光谱与制备的氢化非晶硅薄膜的相应测量结果基本一致，由此确定的光学常量也更接近实际量值。该方法的运算过程不基于最小值优化算法，无需复杂软件辅助，是准确确定表面粗糙薄膜的厚度以及光学常量的一种有效方法。

The transmission and reflection spectra of the rough thin films are directly affected by the surface roughness. If this effect is not taken into account, there will be evident error for the calculation of thickness and optical constants of rough thin films. Using the scalar wave scattering theory, the light scattering caused by rough film surface is analyzed in detail by introducing the surface root mean square roughness, and the transmittance expression of the thin film system is obtained. On this basis, the calculated film thickness and transmission spectrum are in agreement with the measurement results of the prepared hydrogenated amorphous silicon (a-SiH) thin film. The determined optical constants are closer to the actual ones. Because the calculation process is not based on the minimum value optimization algorithm and does not need the aid of complicated software, it is an effective and exact method to determine the thickness and optical constants of rough thin films.