Practical application of direct electron detectors to EBSD mapping in 2D and 3D

Area of Science:

• Materials Science
• Microscopy
• Crystallography

Background:

• Electron backscatter diffraction (EBSD) is crucial for analyzing material microstructures.
• Conventional EBSD often requires sample movement, complicating 3D data acquisition.
• Focused ion beam (FIB) microscopy offers high resolution but requires specific sample-detector geometries.

Purpose of the Study:

• To demonstrate the use of a direct electron detector for 2D and 3D EBSD mapping in a FIB-SEM.
• To evaluate the benefits of static sample geometry for EBSD data acquisition.
• To identify challenges and solutions for integrating direct electron detectors in FIB-SEM.

Main Methods:

• Utilized a Medipix direct electron detector mounted on the same stage as the sample in a FIB-SEM.
• Acquired 2D EBSD maps and 3D EBSD datasets with a static sample.
• Compared data with conventional phosphor-based EBSD detectors that necessitate sample movement.
• Employed fiducial marks to stabilize the sample during data acquisition.

Main Results:

• The direct electron detector enabled simple acquisition of 2D and 3D EBSD data with static sample geometry.
• Static sample geometry resulted in improved slice registration for 3D EBSD datasets.
• Significant sample drift was observed due to detector heating.
• Fiducial marks and ion beam reheating were necessary to maintain sample stability.

Conclusions:

• Direct electron detectors are suitable for EBSD mapping in FIB-SEM, offering advantages in data acquisition simplicity and registration.
• Sample heating by the detector is a key challenge that can be mitigated using fiducial marks.
• Further optimization is needed to address sample drift in static sample EBSD configurations.