Effect of Fe impurity on the dislocations in 4H-SiC: Insights from electrical and optical characterization

The effect of Fe impurity on the dissociation and motion behavior of basal plane dislocations (BPDs) in 4H-SiC homoepitaxial layers was investigated by electron-beam-induced current (EBIC) and cathodoluminescence (CL) techniques. Under the electron-beam irradiation, the BPDs dissociated to C- and Si-core partials, and these two partials were connected by another partial termed as X in this study. Stacking faults (SFs) were formed among these partials. The recombination activities of the BPDs and partials were enhanced with the existence of Fe impurity. The SFs near the surface region showed obvious dark contrast in EBIC, which was different from that observed in the clean samples. The X partial kept moving with sustained electron-beam irradiation whereas this partial in the clean samples stopped motion when it was connected to the sample surface. The dark contrast of the SFs and the peculiar motion behavior of the X partial are discussed with the CL results.