Single crystal growth of SiC substrate material for blue light emitting diodes

The fabrication of 6H-SiC ingot single crystals with up to 20-mm diam and 24-mm length is described. Crystal growth was realized with a modified Lely method using a suitable seed crystal. The growth temperature was 2200°C to obtain preferential growth of the 6H-modification with 2.9-eV bandgap useful for blue light emitting silicon carbide diodes. It is the first time that 6H-SiC ingot crystals yielding substrates for the industrial production of devices based on this compound were obtained. With controlled Al doping of the crystal it was possible to fabricate blue light diodes with the highest quantum efficiency reported so far.