Aluminum nitride bulk single‐crystal with a diameter of 64 mm has been characterized using transmission electron microscopy (TEM). Threading dislocations (TDs), basal plane dislocations (BPDs), and low‐angle boundaries have been observed, and their interactions have been investigated. Special attention was given to the basal–plane slip of –screw and mixed dislocations. By analyzing the Burgers vectors and line orientations using different diffraction vectors, the reaction of a BPD with a wall of inclined TDs was determined. The transformation of an inclined TD into a BPD was observed. The obtained results confirm that dislocations do not simply thread along the growth axis. The formal concept of defect propagation gives way to a deliberate consideration of their evolution during early and more advanced stages of crystal growth.
Myasoedov et al. (2026) studied this question.