Controlling impurity distribution in quasi-mono crystalline Si ingot by seed manipulation for artificially controlled defects technique

We report on our attempt to control impurity distributions by locally introduced high density of dislocations based on seed manipulation for artificially controlled defect technique (SMART). To grow a quasi-mono crystalline Si ingot to demonstrate the impact of SMART, seed arrangement was designed to have SMART and conventional parts in a single ingot. After crystal growth, the ingot was cut in half and the half one was annealed at 600 °C for 1 week. Photoluminescence imaging clarified that impurities are efficiently trapped at functional defects after annealing, which led to improvement of the crystal quality along the functional defects. This result suggests that combining SMART with annealing after crystal growth is the effective way to obtain a higher manufacturing yield of quasi-mono crystalline Si ingot for solar cells.