In the fabrication GaN-based devices, several growth orientations are currently under investigation in order to exploit material properties which are inaccessible using layers grown along the c-axis. However, such procedures rely on foreign substrates with large misfits. Therefore, complex crystallographic defects form in the epitaxial layers and have been the subject of extensive studies. They include threading dislocations and stacking faults, which can be within basal or prismatic planes. Out of the c-axis, depending on the growth orientation, the glide planes of perfect dislocations may be no longer available, complicating the relaxation processes.