Wu M Y, Huang Q S, Le Guen K, Ilakovac V, Li B X, Wang Z S, Giglia A, Rueff J P, Jonnard P
Laboratoire de Chimie Physique - Matière et Rayonnement, Sorbonne University, UMR CNRS 7614, 4 Place Jussieu, 75005 Paris, France.
Key Laboratory of Advanced Micro-Structured Materials MOE, Institute of Precision Optical Engineering, School of Physics Science and Engineering, Tongji University, Shanghai 200092, People's Republic of China.
J Synchrotron Radiat. 2018 Sep 1;25(Pt 5):1417-1424. doi: 10.1107/S1600577518009402. Epub 2018 Aug 9.
Pd/Y multilayers are high-reflectance mirrors designed to work in the 7.5-11 nm wavelength range. Samples, prepared by magnetron sputtering, are deposited with or without BC barrier layers located at the interfaces of the Pd and Y layers to reduce interdiffusion, which is expected from calculating the mixing enthalpy of Pd and Y. Grazing-incident X-ray reflectometry is used to characterize these multilayers. BC barrier layers are found to be effective in reducing Pd-Y interdiffusion. Details of the composition of the multilayers are revealed by hard X-ray photoemission spectroscopy with X-ray standing wave effects. This consists of measuring the photoemission intensity from the samples by performing an angular scan in the region corresponding to the multilayer period and an incident photon energy according to Bragg's law. The experimental results indicate that Pd does not chemically react with B nor C at the Pd-BC interface while Y does react at the Y-BC interface. The formation of Y-B or Y-C chemical compounds could be the reason why the interfaces are stabilized. By comparing the experimentally obtained angular variation of the characteristic photoemission with theoretical calculations, the depth distribution of each component element can be interpreted.
钯/钇多层膜是设计用于在7.5 - 11纳米波长范围内工作的高反射镜。通过磁控溅射制备的样品，在钯层和钇层的界面处有或没有BC阻挡层的情况下进行沉积，以减少互扩散，互扩散可通过计算钯和钇的混合焓来预期。掠入射X射线反射测量法用于表征这些多层膜。发现BC阻挡层在减少钯 - 钇互扩散方面是有效的。具有X射线驻波效应的硬X射线光电子能谱揭示了多层膜组成的细节。这包括通过在对应于多层膜周期的区域内进行角度扫描并根据布拉格定律选择入射光子能量来测量样品的光发射强度。实验结果表明，在钯 - BC界面处钯与硼和碳不发生化学反应，而在钇 - BC界面处钇会发生反应。钇 - 硼或钇 - 碳化合物的形成可能是界面稳定的原因。通过将实验获得的特征光发射的角度变化与理论计算进行比较，可以解释各组成元素的深度分布。
