Lamellae preparation for atomic-resolution STEM imaging from ion-beam-sensitive topological insulator crystals

• Published in: Journal of vacuum science & technology. A, Vacuum, surfaces, and films Vol. 40; no. 3
• Main Authors: Bake, Abdulhakim, Zhao, Weiyao, Mitchell, David, Wang, Xiaolin, Nancarrow, Mitchell, Cortie, David
• Format: Journal Article
• Language: English
• Published: 01-05-2022
• ISSN: 0734-2101; 1520-8559
• DOI: 10.1116/6.0001771

Good specimen quality is a key factor in achieving successful scanning transmission electron microscope analysis. Thin and damage-free specimens are prerequisites for obtaining atomic-resolution imaging. Topological insulator single crystals and thin films in the chalcogenide family such as Sb2Te3 are sensitive to electron and ion beams. It is, therefore, challenging to prepare a lamella suitable for high-resolution imaging from these topological insulator materials using standard focused ion-beam instruments. We have developed a modified method to fabricate thin focused ion-beam (FIB) lamellae with minimal ion-beam damage and artifacts. The technique described in the current study enables the reliable preparation of high-quality transmission electron microscope (TEM) specimens necessary for studying ultra-thin surface regions. We have successfully demonstrated that the careful selection of FIB milling parameters at each stage minimizes the damage layer without the need for post-treatment.