Micrometer-Scale Deep-Level Spectral Photoluminescence From Dislocations in Multicrystalline Silicon

Micrometer-scale deep-level spectral photoluminescence (PL) from dislocations is investigated around the subgrain boundaries in multicrystalline silicon. The spatial distribution of the D lines is found to be asymmetrically distributed across the subgrain boundaries, indicating that defects and impurities are decorated almost entirely on one side of the subgrain boundaries. In addition, the D1 and D2 lines are demonstrated to have different origins due to their significantly varying behaviors after processing steps. D1 is found to be enhanced when the dislocations are cleaned of metal impurities, whereas D2 remains unchanged. Finally, the D4 and D3 lines are proposed to have different origins since their energy levels are shifted differently as a function of distance from the subgrain boundaries.