Reducing ion beam damage from the focused ion beam (FIB) during fabrication of cross sections is a well-known challenge for materials characterization, especially cross sectional characterization of nanostructures. To address this, a new method has been developed for cross section fabrication enabling high resolution transmission electron microscopy (TEM) analysis of 3-D nanostructures free of surrounding material and free of damage detectable by TEM analysis. Before FIB processing, nanopillars are encapsulated in a sacrificial oxide which acts as a protective layer during FIB milling. The cross sectional TEM lamella containing the nanopillars is then mounted and thinned with some modifications to conventional FIB sample preparation that provide stability for the lamella during the following wet-chemical dip etch. The wet-chemical etch of the TEM lamella removes the sacrificial oxide layer, freeing the nanopillars from any material that would obscure TEM imaging. Both high resolution TEM and aberration corrected scanning TEM images of Si/SiGe pillars with diameters down to 30 nm demonstrate the successful application of this approach.

中文翻译：

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FIB 提拉 TEM 薄片的湿化学蚀刻，用于 3-D 纳米结构的无损伤分析

在横截面制造过程中减少聚焦离子束 (FIB) 的离子束损伤是材料表征的众所周知的挑战，尤其是纳米结构的横截面表征。为了解决这个问题，开发了一种新的横截面制造方法，能够对 3-D 纳米结构进行高分辨率透射电子显微镜 (TEM) 分析，该结构没有周围材料，并且没有可通过 TEM 分析检测到的损坏。在 FIB 加工之前，纳米柱被封装在牺牲氧化物中，该氧化物在 FIB 铣削过程中充当保护层。然后将包含纳米柱的横截面 TEM 薄片安装并减薄，对常规 FIB 样品制备进行一些修改，在随后的湿化学浸蚀过程中为薄片提供稳定性。TEM 薄片的湿化学蚀刻去除了牺牲氧化物层，将纳米柱从任何会模糊 TEM 成像的材料中释放出来。直径低至 30 nm 的 Si/SiGe 柱的高分辨率 TEM 和像差校正扫描 TEM 图像都证明了这种方法的成功应用。