Ar ion milling system for the selective preparation of TEM specimen

在菲利普斯-马尔堡大学材料科学中心，一台双像差校正的扫描电子显微镜(与其他显微镜一起)在该大学的电子显微镜用户设施中操作。这种显微镜主要用于半导体、离子导体和氧化物等新型功能材料的研究。在几个协同的和单独的项目中，使用了不同的电子显微镜技术--一方面是为了进一步发展电子显微镜技术，另一方面是为了建立所研究的功能材料的结构和性质关系。利用高分辨电子显微镜、高分辨扫描电子显微镜、电子能量损失谱以及四维扫描电子显微镜对材料及其界面进行了定量表征。目前，电子透明样品的制备方法有两种，一种是用聚焦镓离子束球磨，另一种是用宽束Ar离子束球磨。样品表面的严重损坏是这两种制备技术的结果。这些损坏的层使数据的定量评估变得不可能。使用精细聚焦的Ar离子束，可以利用所提出的离子磨机有意地去除损坏的和离子注入的层。这导致了用于电子显微镜研究的样品，这些样品没有损坏的表面层，并且均匀地薄。这不仅有助于提高微观研究的质量，而且使成分和电场的定量研究成为可能，而且还可以跨界面进行。

At the Materials Science Center of Philipps-Universität Marburg a double-aberration corrected scanning transmission electron microscope is operated (amongst other microscopes) in the user facility for electron microscopy of the university. This microscope is used mainly for research in the areas of novel functional materials, like semiconductors, ion conductors, and oxides. In several coordinated as well as individual projects different electron microscopic techniques are used - on the one hand to develop the electron microscopic techniques further and on the other hand to establish a structure <=> property relationship for the functional materials investigated. High resolution transmission electron microscopy, high resolution scanning transmission electron microscopy, electron energy loss spectroscopy are used as well as four-dimensional scanning transmission electron microscopy to characterize the materials and their interfaces quantitatively. Electron transparent samples are currently prepared either by milling using a focused Gallium ion beam or by milling with a broad Argon ion beam. Severe damage of the specimen surfaces is a result of both preparation techniques. These damaged layers make quantitative evaluation of data impossible. The damaged and ion implanted layers can be intentionally removed with the proposed ion mill using a finely focused Argon ion beam. This results in specimens for electron microscopic investigations, which are free from damaged surface layers and which are homogeneously thin. This not only helps to improve the quality of microscopic investigations, but also makes quantitative studies on composition and on electric fields possible, also across interfaces.