Exploring 4D-STEM in SEM with an event-driven direct electron detector: Low-dose, high-speed, and sparse data

Area of Science:

• Materials Science
• Electron Microscopy
• Nanotechnology

Background:

• Four-dimensional scanning electron microscopy (4D-STEM) is established in transmission electron microscopy (TEM) for advanced imaging.
• Implementation of 4D-STEM in scanning electron microscopy (SEM) has been limited.

Purpose of the Study:

• To integrate event-driven direct electron detectors into a focused ion beam scanning electron microscopy (FIB-SEM) system.
• To enable high-speed 4D-STEM applications within SEM for materials characterization.

Main Methods:

• Integration of an event-driven direct electron detector into a FIB-SEM.
• Utilizing a sparse data workflow for fast data processing with high time resolution (1.56 ns).
• Demonstration through three distinct experimental applications.

Main Results:

• Achieved nanoscale crystal orientation mapping of FePt alloy nanoparticles with enhanced diffraction contrast.
• Successfully performed strain mapping on an AlCrFeMnTi high-entropy alloy.
• Acquired high-quality diffraction patterns of CsPbI₃ perovskites at ultralow doses (4.62 × 10⁻³ e⁻/Ų) with ultrafast acquisition (50 ns/pixel) for grain boundary mapping.

Conclusions:

• The integration of 4D-STEM significantly advances SEM capabilities.
• This technology enables high-speed, high-resolution analysis of material properties at the nanoscale.
• Opens new avenues for materials science research using SEM.