Sample preparation for atomic-resolution STEM at low voltages by FIB
Sample preparation for atomic-resolution STEM at low voltages by FIB
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DOI：
10.1016/j.ultramic.2012.01.005
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发表时间：
2012-03-01
期刊：
影响因子：
2.2
通讯作者：
Ramasse, Quentin
中科院分区：
文献类型：
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作者：
Schaffer, Miroslava;Schaffer, Bernhard;Ramasse, Quentin
虽然用于透射电子显微镜的FIB样品制备是一种成熟的技术，但很少有样品具有足够的质量以通过像差校正（扫描）透射电子显微镜（STEM）进行原子分辨率成像。在这项工作中，我们展示了成功的制备这样的样品从五种不同的材料，并提出了精致的抬出制备技术，这是在这里应用。平行的表面和一般的厚度在20和40 nm之间的范围内的几个μ m的样品进行了反复制备和分析Cs-校正的干在60和100千伏。在这里，一种新颖的“楔形预研磨”步骤有助于在整个研磨过程中保持保护表面层的完整性，从而允许分析靠近或位于样品表面的特征，而不会对制备过程造成损坏。另一个实例示出了将工作薄膜太阳能电池器件的横截面制备为在感兴趣区域中的μ m尺寸的区域上的10至20 nm的最终厚度，使得能够在没有投影伪影的情况下跨越一般晶界进行原子分辨率成像和元素映射。所有的样品制备已经进行了现代双光束FIB显微镜能够低kV Ga+离子铣削，但没有额外的准备步骤后，FIB的提升程序。(C)2012爱思唯尔有限公司版权所有。
While FIB sample preparation for transmission electron microscopy is a well established technique, few examples exist of samples of sufficient quality for atomic resolution imaging by aberration corrected (scanning) transmission electron microscopy (STEM). In this work we demonstrate the successful preparation of such samples from five different materials and present the refined lift-out preparation technique, which was applied here. Samples with parallel surfaces and a general thickness between 20 and 40 nm over a range of several mu m were repeatedly prepared and analyzed by Cs-corrected STEM at 60 and 100 kV. Here, a novel 'wedge pre-milling' step helps to keep the protective surface layers intact during the whole milling process, allowing features close to or at the sample surface to be analyzed without preparation damage. Another example shows the cross-sectional preparation of a working thin film solar cell device to a final thickness of 10 to 20 nm over mu m sized areas in the region of interest, enabling atomic resolution imaging and elemental mapping across general grain boundaries without projection artefacts. All sample preparation has been carried out in modern Dual-Beam FIB microscopes capable of low-kV Ga+ ion milling, but without additional preparation steps after the FIB lift-out procedure. (C) 2012 Elsevier B.V. All rights reserved.