基于掠入射X射线反射谱的Mo/Si多层膜扩散系数测量  

Diffusion Coefficient Measurement by Grazing Incidence X-ray Reflection in a Mo/Si Multilayer

作　　者：喻波[1] 李春[1] 金春水[1] 

机构地区：[1]中国科学院长春光学精密机械与物理研究所应用光学国家重点实验室,吉林长春130033

出　　处：《中国激光》2011年第11期214-219,共6页Chinese Journal of Lasers

基　　金：国家科技重大专项资助课题

摘　　要：测量了Mo/Si多层膜在250℃下经历不同时间退火后的掠入射X射线反射谱,从中提取出特定级次衍射峰在退火过程中的相对移位,通过布拉格公式拟合,得到了Mo/Si多层膜周期厚度皮米级别的相对变化。采用扩散控制模型来描述Mo/Si多层膜界面扩散,界面厚度的平方随时间线性增加,由此拟合得到Mo和Si间的扩散系数为0.33×10-22 cm2/s。采用四层模型,对掠入射X射线反射谱进行全谱拟合,得到了Mo,Si和扩散层MoSi2的密度分别为9.3,2.5和5.4g/cm3,据此对Mo和Si间扩散系数进行修正,最终得到在250℃下,Mo/Si多层膜中Mo和Si间的扩散系数为1.88×10-22 cm2/s,从而为研究Mo/Si多层膜的热稳定性提供了定量依据。The grazing incidence X-ray reflection spectra of a Mo/Si multilayer annealing at a temperature of 250 ℃ at different time are measured and the relative shifts in Bragg peak positions are extracted, from which the relative period thickness changes of the Mo/Si multilayer at pm-accuracy are calculated by fitting Bragg formula. A diffusion limited model is applied to account for the growing interfaces between Mo and Si, which states that the thickness of a compound interface grows quadratically over time. From this model the diffusion constant figures out to be 0.33 ×10 22 cm2/s. Then the grazing incidence X-ray reflection spectra are fitted by genetic algorithm using four-layer model, with the densities of Mo, Si and MoSi2 determined to be 9.3, 2.5 and 5.4 g/cm3 . Accordingly, the diffusion constant is modified to be 1.88 × 10 22 cm2/s, which gives a quantitative criterion for investigating the thermal stability of the Mo/Si multilayer.

关 键 词：薄膜 MO/SI多层膜 扩散系数 掠入射X射线反射谱 四层模型 极紫外 

分 类 号：O484.5[理学—固体物理] O434.19[理学—物理]