NEAR-EQUILIBRIUM GROWTH OF MICROPIPE-FREE 6H-SIC SINGLE-CRYSTALS BY PHYSICAL VAPOR TRANSPORT

A process for growing micropipe-free single crystals has been develope d by using the modified Lely method, The process parameters were: kept dose to thermal equilibrium. The maximum average thermal gradient ins ide the growth furnace leading to micropipe-free growth was 5 K/cm., A gradient of 7.5 K/cm already resulted in a strong defect formation an d produced a high density of micropipes (>200cm(-2)). The highest achi eved growth rate providing micropipe-free growth was 0.27 mm/h. For th e employed parameter range, 6H-SiC single boule crystals were grown on both the C face and the Si face of 6H-SiC Lely platelets, The grown c rystals :were electrically and optically characterized. (C) 1998 Ameri can Institute of Physics.