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Abstract：
Recently, the dual beam Xe+ plasma focused ion beam (Xe+ pFIB) instrument has attracted increasing interest for site-specific transmission electron microscopy (TEM) sample preparation for a local region of interest as it shows several potential benefits compared to conventional Ga+ FIB milling. Nevertheless, challenges and questions remain especially in terms of FIB-induced artefacts, which hinder reliable S/TEM microstructural and compositional analysis. Here we examine the efficacy of using Xe+ pFIB as compared with conventional Ga+ FIB for TEM sample preparation of Al alloys. Three potential source of specimen preparation artefacts were examined, namely: (1) implantation-induced defects such as amophisation, dislocations, or \'bubble\' formation in the near-surface region resulting from ion bombardment of the sample by the incident beam; (2) compositional artefacts due to implantation of the source ions and (3) material redeposition due to the milling process. It is shown that Xe+ pFIB milling is able to produce improved STEM/TEM samples compared to those produced by Ga+ milling, and is therefore the preferred specimen preparation route. Strategies for minimising the artefacts induced by Xe+ pFIB and Ga+ FIB are also proposed. LAY DESCRIPTION: FIB (focused ion beam) instruments have become one of the most important systems in the preparation of site-specific TEM specimens, which are typically 50-100 nm in thickness. TEM specimen preparation of Al alloys is particularly challenging, as convention Ga-ion FIB produces artefacts in these materials that make microstructural analysis difficult or impossible. Recently, the use of noble gas ion sources, such as Xe, has markedly improved milling speeds and is being used for the preparation of various materials. Hence, it is necessary to investigate the structural defects formed during FIB milling and assess the ion-induced chemical contamination in these TEM samples. Here we explore the feasibility and efficiency of using Xe+ PFIB as a TEM sample preparation route for Al alloys in comparison with the conventional Ga+FIB.
摘要：
最近,双束Xe+等离子体聚焦离子束(Xe+pFIB)仪器已经吸引了对针对感兴趣的局部区域的特定部位透射电子显微镜(TEM)样品制备的越来越多的兴趣,因为与常规Ga+FIB铣削相比,它显示了几个潜在的益处。然而，挑战和问题仍然存在，特别是在FIB引起的人工制品方面，这阻碍了可靠的S/TEM微观结构和成分分析。在这里，我们研究了使用Xe+pFIB与常规Ga+FIB相比用于铝合金的TEM样品制备的功效。检查了样品制备伪影的三个潜在来源，即：（1）植入诱导的缺陷，如两性化，位错,或由于入射光束对样品的离子轰击而在近表面区域中形成气泡；（2）由于源离子的注入而引起的成分伪影和（3）由于铣削过程而引起的材料再沉积。结果表明，与Ga研磨相比，XepFIB研磨能够产生改进的STEM/TEM样品，因此是首选的标本制备路线。还提出了用于最小化由Xe+pFIB和Ga+FIB诱导的伪影的策略。LAY描述：FIB（聚焦离子束）仪器已成为制备特定地点TEM标本的最重要系统之一，其厚度通常为50-100nm。铝合金的TEM试样制备尤其具有挑战性,按照惯例，Ga离子FIB会在这些材料中产生伪像，使微结构分析变得困难或不可能。最近,使用惰性气体离子源，比如Xe,具有显著提高的研磨速度和被用于制备各种材料。因此，有必要研究FIB铣削过程中形成的结构缺陷，并评估这些TEM样品中离子诱导的化学污染。在这里，我们探讨了与常规GaFIB相比，使用XePFIB作为Al合金的TEM样品制备路线的可行性和效率。
