Dislocation proliferation at the growth crystal/seed interface of physical vapor transport-grown 4H-SiC crystals

Abstract 4H-SiC single crystals with different types of seed crystals at a 4° angle were grown by the physical vapor transport method. To enlarge the observed area of the seed crystal/newly grown crystal interface, the wafer was machined at a 2° angle. The longitudinal optical phonon‒plasmon coupled (LOPC) mode was tested by a laser Raman spectrometer, and the location of the growth interface was determined by evaluating the free carrier concentration at the seed‒crystal interface. The defect structure at the seed-crystal/newly grown crystal interface and in nearby regions was studied by high-resolution X-ray diffractometry. The change in stress at the interface was characterized by a stress tester, which showed that the greater the stress at the interface was, the more the dislocations proliferated. The dislocation morphologies in the interfacial regions of different seed grains etched by molten KOH were observed via microscopy.