Sn dopant transport and uniformity in β -Ga 2 O 3 crystal growth by the edge-defined film-fed growth method

Dopant segregation during crystal growth can lead to non-uniform dopant distributions, compromising material uniformity and device reliability. Experimental studies have shown that the crystallization interface shape significantly affects dopant distribution in β -Ga 2 O 3 crystals grown by the edge-defined film-fed growth (EFG) method; however, the underlying mechanisms remain unclear. To address this issue, a global three-dimensional numerical model of β -Ga 2 O 3 crystal growth by the EFG method is developed by coupling dynamic crystallization interface tracking with dopant transport. The simulations reveal that both convective and diffusive transport play important and comparable roles in determining the dopant distribution within the liquid bridge. The crystallization interface shape affects dopant segregation at the crystallization front by modifying both the convective flow and the diffusion pathways of the dopant. In particular, increasing the liquid-bridge thickness reduces the resistance to lateral dopant diffusion, thereby enhancing lateral dopant redistribution and improving dopant uniformity. Based on this mechanistic understanding, a die structure with a top groove is found to provide an additional advantage in dopant uniformity while maintaining a convex crystallization interface favorable for growth stability. These results demonstrate that diffusion transport, together with convection, is an important mechanism governing dopant redistribution during β -Ga 2 O 3 crystal growth by the EFG method, provide fundamental insight into the coupling between crystallization interface shape and mass transport, and offer practical guidance for improving dopant uniformity.