入射光单色性与界面粗糙度对多层膜反射性能的不同影响

多层膜界面粗糙度、入射光单色性对软X射线多层膜实际反射率均有影响。利用数学卷积积分,理论上推导出一个在入射光不同单色性下精确计算多层膜反射率的公式。利用给出的理论计算公式,简要分析了入射光不同单色性、不同界面粗糙度对Mo/Si多层膜反射率的影响。理论分析发现这两种因素对Mo/Si多层膜反射率影响完全不同:入射光低的单色性不但极大降低Mo/Si多层膜峰值反射率,而且使反射曲线的半峰全宽增加;而界面粗糙度是降低Mo/Si多层膜反射曲线上各点对应值,基本不改变Mo/Si反射曲线的半峰全宽,不改变反射曲线的形状。说明这两个因素在软X射线的长波段对多层膜反射性能的影响不同。

Effect of Energy Monochromaticity and Interfacial Roughness on Multilayer Reflectivity

Both the interfacial roughness of multilayer and energy Monochromaticity of the incident light influence the practical reflectivity of multilayer.With convolution integral,a new formulation for describing the relation of soft X-ray reflectivity of multilayer with the different energy Monochromaticity of incident light is deduced.Using this formulation,the effect of different energy Monochromaticity and interfacial roughness on the reflectivity spectrum of Mo/Si multilayer is analyzed respectively.The results of theoretical analysis show that the low energy resolution reduces sharply the peak reflectivity of Mo/Si multilayer but increases the background intensity,which leads to the increase of the full width of half maximum of reflectivity spectrum and the distortion of reflectivity spectrum.However,the interfacial roughness of multilayer only decreases the value of the reflectivity and does not change the shape of reflectivity spectrum and full width of half maximum of reflectivity spectrum.These results illustrate that the influence of energy Monochromaticity of incident light on the reflectance of multilayers is different from that of the interfacial roughness.