The Impact of Dislocation Structure on Impurity Decoration of Dislocation Clusters in Multicrystalline Silicon

Abstract

Light microscopy, electron backscatter diffraction and transmission electron microscopy is employed to investigate dislocation structure and impurity precipitation in commonly occurring dislocation clusters as observed on defect-etched directionally solidified multicrystalline silicon wafers. The investigation shows that poligonised structures consist of parallel mostly similar, straight, well-ordered dislocations, with minimal contact-interaction and no evidence of precipitate decoration. On the other hand, disordered structures consist of various dislocation types, with interactions being common. Decoration of dislocations by second phase particles is observed in some cases. Enhanced recombination activity of dislocations may therefore be a result of dislocation interaction forming tangles, microscopic kinks and jogs, which can serve as heterogeneous nucleation sites that enhance metallic decoration.