Generation mechanism of dislocations during directional solidification of multicrystalline silicon using artificially designed seed

We investigated the generation mechanism of dislocations by comparing dislocation occurrence in multicrystalline silicon with calculated results of the shear stress on the slip plane by finite element analysis. To mimic the multicrystalline Si and to observe structural modification around grain boundaries a model crystal growth set-up was applied using artificially designed seed. We found that the dislocations occur at grain boundary and propagate as crystal growth proceeds. The generation of dislocations was not spatially uniform but often localized in one of the grains. The calculated stress distribution, which depends on crystallographic orientation, implies that the shear stress on the slip plane around the grain boundary is likely to cause occurrence of dislocations.