Abstract：
Chemically resolved atomic resolution imaging can give fundamental information about material properties. However, even today, a technique capable of such achievement is still only an ambition. Here, we take further steps in developing the analytical field ion microscopy (aFIM), which combines the atomic spatial resolution of field ion microscopy (FIM) with the time-of-flight spectrometry of atom probe tomography (APT). To improve the performance of aFIM that are limited in part by a high level of background, we implement bespoke flight path time-of-flight corrections normalized by the ion flight distances traversed in electrostatic simulations modeled explicitly for an atom probe chamber. We demonstrate effective filtering in the field evaporation events upon spatially and temporally correlated multiples, increasing the mass spectrum\'s signal-to-background. In an analysis of pure tungsten, mass peaks pertaining to individual W isotopes can be distinguished and identified, with the signal-to-background improving by three orders of magnitude over the raw data. We also use these algorithms for the analysis of a CoTaB amorphous film to demonstrate application of aFIM beyond pure metals and binary alloys. These approaches facilitate elemental identification of the FIM-imaged surface atoms, making analytical FIM more precise and reliable.
摘要：
化学分辨原子分辨率成像可以提供有关材料特性的基本信息。然而,即使在今天,一种能够实现这种成就的技术仍然只是一种抱负。这里,我们在开发分析场离子显微镜(aFIM)方面采取了进一步的措施，将场离子显微镜（FIM）的原子空间分辨率与原子探针断层扫描（APT）的飞行时间光谱相结合。为了提高受高水平背景限制的aFIM的性能，我们实现了定制的飞行路径飞行时间校正，通过在为原子探针室明确建模的静电模拟中遍历的离子飞行距离进行归一化。我们证明了在空间和时间相关倍数下的场蒸发事件中的有效过滤，增加质谱的信号到背景。在对纯钨的分析中，可以区分和识别与单个W同位素有关的质量峰，背景信号比原始数据提高了三个数量级。我们还使用这些算法来分析CoTaB非晶膜，以证明aFIM在纯金属和二元合金之外的应用。这些方法有助于FIM成像表面原子的元素识别，使分析FIM更加精确和可靠。
