Analysis on defect generation during the SiC bulk growth process

SiC crystals (1.2-1.5 " diameter) were grown by the modified Lely technique on seeds with different micropipe densities in order to study the defect generation during seeding and subsequent bulk growth. The micropipe generation is found to be strongly correlated with the occurrence of second phases in SiC like carbon inclusion formation. Model approaches for stable SiC growth conditions, i.e. without inclusions, are discussed. Numerical modeling was performed to reveal the radial and axial temperature gradients of our crucible set-up. Stress formation and micropipe generation are determined to be enhanced in the presence of a large axial temperature gradient. (C) 1999 Elsevier Science S.A. All rights reserved.