Mo/Si多层膜小角X射线衍射结构表征

为了实现对Mo/Si多层膜的结构表征,测量了多层膜样品的小角X射线衍射谱。介绍了小角X射线衍射谱的分析方法,包括Bragg峰值拟合法,傅里叶变换法,反射谱拟合法。Bragg峰值拟合法和反射谱拟合法得到多层膜的周期厚度为7.09nm,两种模型的反射谱拟合法得到界面的粗糙度(扩散长度)为0.40～0.41nm(Si在Mo上),0.52～0.70nm(Mo在Si上),前者要比后者小,这与透射电镜法(TEM)得到的结果0.40nm(Si在Mo上),0.6～0.65nm(Mo在Si上)是一致的。通过基于扩散模型的反射谱拟合法得到的折射率剖面也与由高倍率透射电镜(HRTEM)积分得到的灰度值剖面在趋势上是一致的。通过X射线衍射谱和TEM图像对Mo/Si多层膜进行综合表征,得到了多层膜的精细结构信息,这对多层膜制备工艺的优化具有十分重要的意义。

Structural characterization of Mo/Si multilayer by grazing incidence X-ray diffraction

In order to characterize the structure of a Mo/Si multilayer, the Small Angle X-ray Diffraction(SAXD) of a multilayer sample is measured and the analytical methods of SAXD data were introduced, including Bragg peak fitting, Fourier transform, and X-ray diffraction fitting. The period thickness of the multilayer obtained by the Bragg peak fitting or X-ray diffraction curve fitting is 7.09 nm. The interface roughness(interdiffusion length) are 0.40-0.41 nm(Si on Mo) and 0.52-0.70 nm(Mo on Si), respectively. And the former is smaller than latter, which is consistent with the Transmisson Electron Microscopy(TEM) results in 0.40 nm(Si on Mo) and 0.6-0.65 nm(Mo on Si). Meanwhile, the refractive profile extracted by the X-ray diffraction fitting with a diffusion model is also consistent with the gray-scale profile by integrated High Resolution TEM(HRTEM). By the comprehensive characterization of the X-ray diffractometry(XRD) and TEM, the fine structural information of the Mo/Si multilayer is obtained, which is critical for the technology optimization of the multilayer deposition.