Control of Grain Boundary Propagation in Mono-Like Si: Utilization of Functional Grain Boundaries

We attempted to control grain boundary propagation in mono-like Si utilizing functional grain boundaries introduced by multi-seeds with specific configurations, and demonstrated that functional grain boundaries can suppress multi-crystallization during growth. The suppression mechanism was studied on the basis of grain boundary character. The grain boundaries nucleate at the crucible surface, which generally leads to multi-crystallization, interact with the functional grain boundaries, resulting in a change of their character and configuration. This would increase the yield of the mono-like wafers in an ingot and would enable a large reduction of cost per watt of solar cells.