Fabrication and Characterization of Photoconductive AlGaN Detectors/ Structural Characterization of SiC Wafers

摘要

Structure of silicon carbide wafers have been evaluated by x-ray topography, high resolution x-ray diffraction, etching, Atomic Force Microscopy, and related techniques. The low angle grain boundaries were imaged by White Beam Synchrotron X-Ray Topography and mis-orientations quantitatively mapped out by x-ray diffraction. The dominant component of mis-orientation was basal plane tilt. The formation mechanism is most likely due to buckling of the rigidly mounted SiC seed during initial stages of growth. The morphology of hexagonal voids was studied by optical microscopy and AFM. Voids originate at the seed crystal/crucible lid interface and move through the boule during growth. Interaction of void and grown in dislocations leads to formation of dislocation arrays and open core screw dislocations underneath the void. It appears to be the dominant formation mechanism of micropipes.