Busch Richard, Krause Michael, Coyle Steve, Höche Thomas
Fraunhofer Institute for Microstructure of Materials and Systems IMWS, Walter-Hülse-Straße 1, 06120 Halle (Saale), Germany.
Gatan Inc., 5794 W. Las Positas Blvd., Pleasanton, CA 94588, United States.
Micron. 2018 Apr;107:35-42. doi: 10.1016/j.micron.2018.01.002. Epub 2018 Jan 31.
Glancing-angle Ar broad ion beam erosion is widely used for the preparation of high-quality transmission electron microscopy (TEM) samples. However, low erosion rates and lack of site specificity are major drawbacks of the method. Being inexpensive and easy to use - in particular when compared to widely used focused ion beam preparation methods - overcoming these drawbacks would significantly improve many existing preparation workflows. We present a novel method for rapid and localized surface erosion which combines laser-machining preprocessing with broad ion beam etching. In this article, preliminary studies of the method on bulk samples are reported. Furthermore, an electron-transparent lamella has been prepared as proof of concept. Using an ultrashort-pulsed solid-state laser, notches were created on (100)-Si substrates. Due to the local change in surface inclination, preferential erosion took place behind the notches upon subsequent ion beam etching at glancing angles. As a consequence, a terrace structure possessing a well-defined jump in surface height was formed. The surface topography and its evolution dynamics were characterized and the findings compared to numerical simulations based on a deterministic, two-dimensional model. On this basis, a workflow utilizing these initial notches (iNotches™) for the preparation of an electron transparent lamella was realized and TEM micrographs of the prepared sample were taken.
掠角氩宽离子束侵蚀广泛用于高质量透射电子显微镜（TEM）样品的制备。然而，低侵蚀速率和缺乏位点特异性是该方法的主要缺点。该方法价格低廉且易于使用——特别是与广泛使用的聚焦离子束制备方法相比——克服这些缺点将显著改善许多现有的制备工作流程。我们提出了一种将激光加工预处理与宽离子束蚀刻相结合的快速局部表面侵蚀新方法。本文报道了该方法对块状样品的初步研究。此外，还制备了一个电子透明薄片作为概念验证。使用超短脉冲固态激光器，在（100）硅衬底上制作了切口。由于表面倾斜度的局部变化，在随后的掠角离子束蚀刻过程中，切口后方发生了优先侵蚀。结果，形成了一个表面高度有明确跃变的台阶结构。对表面形貌及其演化动力学进行了表征，并将结果与基于确定性二维模型的数值模拟进行了比较。在此基础上，实现了利用这些初始切口（iNotches™）制备电子透明薄片的工作流程，并拍摄了制备样品的TEM显微照片。
