Dark field electron holography for strain measurement

• Published in: Ultramicroscopy Vol. 111; no. 3; pp. 227 - 238
• Main Authors: Béché, A., Rouvière, J.L., Barnes, J.P., Cooper, D.
• Format: Journal Article
• Language: English
• Published: Netherlands Elsevier B.V 01.02.2011
• Subjects: Beams (radiation); Dark field electron holography; Electric potential; Holograms; Holography; Mathematical analysis; Silicon; Silicon germanides; Strain; Strain measurement; Transmission electron microscopy; Dark field electron holography; Transmission electron microscopy; Strain
• ISSN: 0304-3991; 1879-2723
• DOI: 10.1016/j.ultramic.2010.11.030

Dark field electron holography is a new TEM-based technique for measuring strain with nanometer scale resolution. Here we present the procedure to align a transmission electron microscope and obtain dark field holograms as well as the theoretical background necessary to reconstruct strain maps from holograms. A series of experimental parameters such as biprism voltage, sample thickness, exposure time, tilt angle and choice of diffracted beam are then investigated on a silicon-germanium layer epitaxially embedded in a silicon matrix in order to obtain optimal dark field holograms over a large field of view with good spatial resolution and strain sensitivity. ► Step by step explanation of the dark field electron holography technique. ► Presentation of the theoretical equations to obtain quantitative strain map. ► Description of experimental parameters influencing dark field holography results. ► Quantitative strain measurement on a SiGe layer embedded in a silicon matrix.