Punching of Prismatic Dislocation Loops from Inclusions in 4H-SiC Wafers

Indentation behavior induced by the presence of foreign inclusions in a PVT-grown 4H-SiC wafer is investigated through synchrotron X-ray topography, which revealed the generation of dislocation arrays from the inclusion center along six <11-20> directions. Grazing-incident topographs shows these dislocation arrays exhibit contrast configurations of opposite-signed TED pairs or BPD segments. This correlates with dislocation loops generated due to prismatic punching, and dislocation configuration variation is dependent on the position of prismatic loops with respect to the wafer surface. The stress induced by the inclusion embedded in the 4H-SiC matrix is estimated from the difference in the thermomechanical properties, as the crystal is cooled from the growth temperature.