Crystal orientation mapping via ion channeling: An alternative to EBSD

Current methods for mapping crystal orientation in polycrystalline materials often rely on electron backscatter diffraction (EBSD). While EBSD is widely used, it has limitations in certain materials and conditions. Researchers have long sought alternative techniques that can provide similar or better resolution without these constraints. Some studies have explored ion beam interactions with crystalline structures, but no comprehensive method has yet emerged. This gap motivated the development of a new approach based on ion channeling effects. Ion channeling is a well-known phenomenon where ions follow crystallographic channels, reducing scattering. This behavior can influence secondary electron emission in focused ion beam systems. Prior research has shown that ion beam tilt can affect image contrast in such systems. However, no prior work had resolved how to systematically extract orientation data from these effects.

The study aimed to develop a new method for mapping crystal orientation in polycrystalline materials. The researchers focused on using ion channeling to generate orientation data. They proposed a technique called iCHORD, which uses secondary electron image contrast. The goal was to create a reliable alternative to EBSD. The method relies on the relationship between ion beam orientation and image intensity. The researchers wanted to test if this relationship could be used to determine crystallographic orientation. They also sought to evaluate the method’s accuracy and potential applications. The titanium nitride sample was selected to demonstrate the feasibility of the approach.

The iCHORD method involves acquiring secondary electron images from a polycrystalline sample. The images are taken at different ion beam tilt angles relative to the sample. At each point in the region of interest, intensity profiles are extracted from these images. The profiles are compared to a database of theoretical intensity patterns. The database contains precomputed profiles for known crystal orientations. The orientation associated with the closest match is assigned to the sample point. This process is repeated across the entire region of interest. The titanium nitride sample was used to validate the method’s performance.

The iCHORD method successfully mapped crystal orientation in the titanium nitride sample. The orientation data matched the expected crystallographic structure. The method achieved spatial resolution comparable to EBSD techniques. The secondary electron intensity profiles showed clear orientation dependence. The database comparison correctly identified the most similar theoretical profiles. The results demonstrated the method’s potential for orientation mapping. The titanium nitride sample provided a strong proof-of-concept. The researchers observed minimal noise in the orientation data.

The iCHORD method provides a viable alternative to EBSD for crystal orientation mapping. The results show that ion channeling can be used to extract orientation data. The method relies on secondary electron image contrast and theoretical profile matching. The titanium nitride sample confirmed the technique’s feasibility. The researchers propose that iCHORD could be applied to other materials. The method may offer advantages in certain experimental conditions. The study suggests further testing on different polycrystalline samples. The authors highlight the potential for broader adoption of the technique.