Combining 4D Scanning Transmission Electron Microscopy and Electron Precession for Mapping of Electric Field at the Nanoscale Over Large Field of View

Nanometer-scale resolution 2D junction electric field or potential profile mapping can provide valuable information for failure analysis, device design and simulation, thus reduces the development cost and cycle time. To date, there are two techniques for high spatial resolution 2D junction electric field mapping: electron holography and 4DSTEM. However, the application of holography for field mapping is limited to the critical experimental requirements and small field of view; the application of the conventional 4DSTEM technique for field mapping is limited to dynamical diffraction and beam scanning artefacts. In this paper, an improved 4DSTEM field mapping technique has been presented: dynamical diffraction artefacts have been suppressed via electron beam precession; beam scanning introduced diffraction pattern shifting has been corrected with reference data. Nanometer-scale resolution, a couple of micrometers field of view and dynamical diffraction artefacts free 2D junction electric field mapping results have been achieved with the improved 4D STEM technique.