Nanometer resolution optical coherence tomography using broad bandwidth XUV and soft x-ray radiation.
Nanometer resolution optical coherence tomography using broad bandwidth XUV and soft x-ray radiation.
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DOI：
10.1038/srep20658
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发表时间：
2016-02-10
影响因子：
4.6
通讯作者：
Paulus GG
中科院分区：
文献类型：
--
作者：
Fuchs S;Rödel C;Blinne A;Zastrau U;Wünsche M;Hilbert V;Glaser L;Viefhaus J;Frumker E;Corkum P;Förster E;Paulus GG
光学相干断层扫描（OCT）是一种非侵入性的横截面成像技术。这对于常规显微镜无法在合理的时间内对样品的更深层成像的应用（例如，在快速移动的更深的结构中）特别有利。然而，在常用的红外和光学波长下，即使光的带宽覆盖很宽的光谱范围，OCT的轴向分辨率也仅限于约1 μm。在这里，我们提出了极紫外相干断层扫描（XCT），从而介绍了一种新的技术，非侵入性的横截面成像的纳米结构。XCT利用对应于光谱透射窗口的纳米尺度相干长度，例如，硅样品。因此，相干层析成像的轴向分辨率从微米提高到几纳米。层析成像的轴向分辨率优于18 nm的层型纳米结构埋在硅基板上证明。使用水透射窗口中的波长，以优于8 nm的分辨率检索纳米级铂层。XCT作为一种非破坏性的亚表面断层成像方法，在半导体计量和水窗成像中有着广泛的应用前景。
Optical coherence tomography (OCT) is a non-invasive technique for cross-sectional imaging. It is particularly advantageous for applications where conventional microscopy is not able to image deeper layers of samples in a reasonable time, e.g. in fast moving, deeper lying structures. However, at infrared and optical wavelengths, which are commonly used, the axial resolution of OCT is limited to about 1 μm, even if the bandwidth of the light covers a wide spectral range. Here, we present extreme ultraviolet coherence tomography (XCT) and thus introduce a new technique for non-invasive cross-sectional imaging of nanometer structures. XCT exploits the nanometerscale coherence lengths corresponding to the spectral transmission windows of, e.g., silicon samples. The axial resolution of coherence tomography is thus improved from micrometers to a few nanometers. Tomographic imaging with an axial resolution better than 18 nm is demonstrated for layer-type nanostructures buried in a silicon substrate. Using wavelengths in the water transmission window, nanometer-scale layers of platinum are retrieved with a resolution better than 8 nm. XCT as a nondestructive method for sub-surface tomographic imaging holds promise for several applications in semiconductor metrology and imaging in the water window.