Scientific and technological progress depend substantially on the ability to image on the nanoscale. In order to investigate complex, functional, nanoscopic structures like, e.g., semiconductor devices, multilayer optics, or stacks of 2D materials, the imaging techniques not only have to provide images but should also provide quantitative information. We report the material-specific characterization of nanoscopic buried structures with extreme ultraviolet coherence tomography. The method is demonstrated at a laser-driven broadband extreme ultraviolet radiation source, based on high-harmonic generation. We show that, besides nanoscopic axial resolution, the spectral reflectivity of all layers in a sample can be obtained using algorithmic phase reconstruction. This provides localized, spectroscopic, material-specific information of the sample. The method can be applied in, e.g., semiconductor production, lithographic mask inspection, or quality control of multilayer fabrication. Moreover, it paves the way for the investigation of ultrafast nanoscopic effects at functional buried interfaces.

中文翻译：

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使用极端紫外相干层析成像技术对纳米层进行材料特定的成像

科学技术的进步很大程度上取决于在纳米级成像的能力。为了研究复杂的功能性纳米结构，例如半导体器件，多层光学器件或2D材料堆栈，成像技术不仅必须提供图像，而且还应提供定量信息。我们报告了具有极端紫外线相干断层扫描的纳米隐埋结构的材料特定的表征。该方法在基于高谐波产生的激光驱动宽带极紫外辐射源上得到了证明。我们表明，除了纳米级的轴向分辨率，还可以使用算法相位重建来获得样品中所有层的光谱反射率。这提供了样品的局部，光谱，特定于材料的信息。该方法可以应用于例如半导体生产，光刻掩模检查或多层制造的质量控制中。而且，它为研究功能性掩埋界面上的超快速纳米效应铺平了道路。