Suppressing SiC crystal edge decomposition through pore-type crucible

As a wide bandgap semiconductor material, silicon carbide (SiC) has promising prospects for application. However, the current commercial production size is limited to six inches, and the challenge of producing larger single crystals increases exponentially as the size grows. The growth of large single crystals is significantly hindered by deteriorating radial growth conditions. This paper proposed a modified crucible structure to improve crystal edge degradation, thereby facilitating the expansion of the crystal diameter. By observing the crystal and the crystallization at the crystal edge and crucible cover, classical nucleation theory was applied to calculate the nucleation process at three potential nucleation sites during the early growth stage: the seed crystal edge, the graphite paper, and the diversion ring. The results indicated that a higher supersaturation ratio facilitated nucleation at the graphite paper, thereby suggesting a potential mechanism for the formation of crystal edge decomposition. To reduce the supersaturation ratio during the early growth stage, a method involving making holes in the crucible cover was proposed. Comparative schemes were conducted with three openings and six openings. The results showed that the six openings crucible effectively reduces the supersaturation ratio during the early growth stage, resulting in the crystal without edge decomposition. Raman and HRXRD-RC results indicated that the crystal had better crystal structure uniformity and higher crystallinity.