Focused ion beam (FIB) sample preparation for electron microscopy often requires large volumes of materials to be removed. Prior efforts to increase the rate of bulk material removal were mainly focused on increasing the primary ion beam current. Enhanced yield of etching at glancing ion beam incidence is known but has not found widespread use in practical applications. In this study, etching at glancing ion beam incidence was explored for its advantages in increasing the rate of bulk material removal. Anomalous enhancement of material removal at glancing angles of ion beam incidence was observed with single-raster etching in along-the-slope direction with toward-FIB direction of raster propagation. Material removal was inhibited in an away-from-FIB direction of raster propagation. The effects of glancing angles and ion doses on depth of cut and volume of removed materials were also recorded. We demonstrated that the combination of single-raster FIB etching at glancing incidence in along-the-slope direction with toward-FIB raster propagation and a “staircase” type of etching strategy holds promise for reducing the processing time for bulk material removal in FIB sample preparation applications.

中文翻译：

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通过以掠入射向离子束传播的单个光栅对聚焦离子束蚀刻的异常增强

用于电子显微镜的聚焦离子束 (FIB) 样品制备通常需要去除大量材料。先前提高大块材料去除率的努力主要集中在增加初级离子束电流上。在掠射离子束入射时提高蚀刻产量是已知的，但尚未在实际应用中广泛使用。在这项研究中，对掠射离子束入射的蚀刻进行了探索，因为它具有提高大块材料去除率的优势。在沿光栅传播的 FIB 方向的斜面方向进行单光栅蚀刻时，观察到在离子束入射的掠射角处材料去除的异常增强。在光栅传播的远离 FIB 方向上，材料去除被抑制。还记录了掠射角和离子剂量对切割深度和去除材料体积的影响。我们证明了将沿斜坡方向的掠入射的单光栅 FIB 蚀刻与朝向 FIB 光栅传播和“阶梯”类型的蚀刻策略相结合，有望减少 FIB 样品中块状材料去除的处理时间准备申请。