3D Strain Measurement of Heterostructures Using the Scanning Transmission Electron Microscopy Moire Depth Sectioning Method

The mechanical properties of micro- and nanoscale materials directly determine the reliability of heterostructures, microstructures, and microdevices. Therefore, an accurate evaluation of the 3D strain field at the nanoscale is important. In this study, a scanning transmission electron microscopy (STEM) moire depth sectioning method is proposed. By optimizing the scanning parameters of electron probes at different depths of the material, the sequence STEM moire fringes (STEM-MFs) with a large field of view, which can be hundreds of nanometers obtained. Then, the 3D STEM moire information constructed. To some extent, multi-scale 3D strain field measurements from nanometer to the submicrometer scale actualized. The 3D strain field near the heterostructure interface and single dislocation accurately measured by the developed method.

Automated summary

In this study, a scanning transmission electron microscopy (STEM) moire depth sectioning method is proposed, which can accurately evaluate the 3D strain field at the nanoscale. Through optimizing the scanning parameters of electron probes at different depths, a large field of view STEM-MFs sequence is obtained, and the 3D STEM moire information is constructed. The developed method realizes multi-scale 3D strain field measurements and accurately measures the 3D strain field near the heterostructure interface and single dislocation.