High-resolution high-sensitivity elemental imaging by secondary ion mass spectrometry: from traditional 2D and 3D imaging to correlative microscopy
High-resolution high-sensitivity elemental imaging by secondary ion mass spectrometry: from traditional 2D and 3D imaging to correlative microscopy
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DOI：
10.1088/0957-4484/26/43/434001
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发表时间：
2015-10-30
期刊：
影响因子：
3.5
通讯作者：
Eswara, S.
中科院分区：
文献类型：
--
作者：
Wirtz, T.;Philipp, P.;Eswara, S.
二次离子质谱 (SIMS) 是一种极其灵敏的 2D 和 3D 表面成像技术。除了出色的灵敏度和高横向分辨率（最先进的 SIMS 仪器为 50 nm）之外，SIMS 的优点还包括高动态范围和区分同位素的能力。本文首先回顾了SIMS的基本原理以及2D和3D SIMS元素成像的性能和应用。讨论了进一步提高 SIMS 成像能力的前景。使用微探针模式时 SIMS 成像的横向分辨率受到以下因素的限制：(i) 离子探针尺寸，这取决于一次离子源的亮度、一次离子柱的光学质量以及用于提取二次离子的近样品区域中的电场； (ii) 分析的灵敏度作为合理的二次离子信号，必须从非常小的体素尺寸以及因此从非常有限数量的溅射原子中检测到； (iii) 碰撞级联的物理尺寸，确定溅射离子相对于入射初级离子探针的撞击位置的起源。一个有趣的前景是基于 SIMS 的关联显微镜的使用。在这种方法中，SIMS 与各种高分辨率显微技术相结合，因此可以使用 SIMS 获得最高灵敏度的元素/化学信息，同时通过将 SIMS 图像与这些显微技术获得的高分辨率图像叠加来提供出色的空间分辨率。通过将 SIMS 与透射电子显微镜 (TEM)、氦离子显微镜 (HIM) 和扫描探针显微镜 (SPM) 进行原位组合，给出了这种方法的示例。
Secondary ion mass spectrometry (SIMS) constitutes an extremely sensitive technique for imaging surfaces in 2D and 3D. Apart from its excellent sensitivity and high lateral resolution (50 nm on state-of-the-art SIMS instruments), advantages of SIMS include high dynamic range and the ability to differentiate between isotopes. This paper first reviews the underlying principles of SIMS as well as the performance and applications of 2D and 3D SIMS elemental imaging. The prospects for further improving the capabilities of SIMS imaging are discussed. The lateral resolution in SIMS imaging when using the microprobe mode is limited by (i) the ion probe size, which is dependent on the brightness of the primary ion source, the quality of the optics of the primary ion column and the electric fields in the near sample region used to extract secondary ions; (ii) the sensitivity of the analysis as a reasonable secondary ion signal, which must be detected from very tiny voxel sizes and thus from a very limited number of sputtered atoms; and (iii) the physical dimensions of the collision cascade determining the origin of the sputtered ions with respect to the impact site of the incident primary ion probe. One interesting prospect is the use of SIMS-based correlative microscopy. In this approach SIMS is combined with various high-resolution microscopy techniques, so that elemental/chemical information at the highest sensitivity can be obtained with SIMS, while excellent spatial resolution is provided by overlaying the SIMS images with high-resolution images obtained by these microscopy techniques. Examples of this approach are given by presenting in situ combinations of SIMS with transmission electron microscopy (TEM), helium ion microscopy (HIM) and scanning probe microscopy (SPM).