We investigated the expansion of single Shockley stacking faults (SSFs) in a 4H-SiC
epitaxial layer under high-intensity scanning laser beam during room temperature photoluminescence
mapping, which is similar to the degradation of bipolar pin diodes during forward current injection.
In an epitaxial layer on an 8 off-axis (0001) substrate, the SSF-related intensity patterns induced by
scanning high-intensity laser beam were classified into two types. The first one was a triangular
pattern and the second a pattern which expanded in accordance with the motion of the scanning laser
beam. The origins of the SSFs responsible for both patterns are presumably due to the preexisting
basal plane dislocations and the dislocation-loops on the basal plane in the epitaxial layer,
respectively. On the other hand, most of the SSF-expansion in on-axis (11 2 0) epitaxial layers were
similar to the second type in the (0001) epitaxial layer. We, therefore, suggest that the
dislocation-loops, which were located close to the surface, were dominant nucleation-sites of the
SSFs in the (11 2 0) epitaxial layers.
Effect of power losses on self-focusing of high-intensity laser beam in gases