The methods of optical microscopy and X-ray diffractometry were used to study the features of defect structure in ingots of the SiC-4H polytype; the ingots had featured different diameters and were grown by the modified Lely method on seeds with deviations of several degrees from the exact orientation (00•1)C in the direction 〈11•0〉 (off-cut (00•1) seeds). The slip bands observed in the crystals were extended along the [11•0] direction and correspond to the secondary slip system of threading dislocations a/3〈11•0〉{¯1•0} for hexagonal close packing crystals. Low-angle dislocation boundaries directed along [1¯•0] accommodate the disorientation of neighbouring domains, which results from their mutual rotation around the [00•1] axis. Enlargement of ingots led to some increase in the dislocation density, mainly due to threading edge dislocations. The average density of micropipes was in the range of 5 to 20/cm2 and practically remained unchanged as the ingot size was increased.

Mechanisms of Defect Formation in Ingots of 4H Silicon Carbide Polytype. D.D.Avrov, A.V.Bulatov, S.I.Dorozhkin, A.O.Lebedev, Y.M.Tairov, A.Y.Fadeev: Semiconductors, 2011, 45[3], 277-83