Growth and Characterization of High-Quality 6H-SiC (0115) Bulk Crystals

Abstract

New results on bulk growth of 6H-SiC crystals along the [01-15] direction are presented. The aim of our work is to improve the quality of the crystal grown by classical PVT method by employing alternative growth directions, other than conventional [0001]. Using a specially designed graphite crucible, crystals with an expansion angle of 30 degrees and diameters up to 40 mm have been grown. No polycrystalline rim develops at the contact with the graphite wall. Concerning specific defect content in the [01-15]-oriented crystals, they appear completely free of micropipes and screw or threading edge ([0001]-oriented) dislocations. The [01-15] crystal relaxes adopting a network of in-plane (0001) dislocations. They are not uniformly distributed reaching the maximum density of about 106 cm-2.