Investigation of Electron–Hole Recombination-Activated Partial Dislocations and Their Behavior in 4H-SiC Epitaxial Layers

Electron–hole recombination-activated partial dislocations in 4H silicon carbide homoepitaxial layers and their behavior have been studied using synchrotron X-ray topography and electroluminescence. Stacking faults whose expansion was activated by electron–hole recombination enhanced dislocation glide were observed to be bounded by partial dislocations, which appear as white stripes or narrow dark lines in back-reflection X-ray topographs recorded using the basal plane reflections. Such contrast variations are attributable to the defocusing/focusing of the diffracted X-rays due to the edge component of the partial dislocations, which creates a convex/concave distortion of the basal planes. Simulation results based on the ray-tracing principle confirm our argument. Observations also indicate that, when an advancing partial dislocation interacts with a threading screw dislocation, a partial dislocation dipole is dragged behind in its wake. This partial dislocation dipole is able to advance regardless of the immobility of the C-core segment. A kink pushing mechanism is introduced to interpret the advancement of this partial dislocation dipole.