Recombination activity of Σ3 boundaries in boron-doped multicrystalline silicon:: Influence of iron contamination -: art. no. 033701

The impact of the boundary plane and impurity contamination on the recombination activity of Sigma3 boundaries in multicrystalline silicon (mc-Si) was studied by means of electron-beam-induced current (EBIC) technique. In the as-grown contamination-free mc-Si, the EBIC contrast of different Sigma3 boundaries was in the order of Sigma3{111}<Sigma3{110}<Sigma3{112}. This order may be attributed to the difference in the defect density of the Sigma3 boundaries due to the effect of the boundary plane. But the maximum EBIC contrast did not exceed 2% at 300 K, suggesting that the Sigma3 boundaries are originally electrically inactive and the boundary plane has no significant effect on their recombination activity. When contaminated with Fe at 900 degreesC, the EBIC contrasts of the Sigma3{110} and Sigma3{112} increased at 300 K, whereas that of the Sigma3{111} was still weak (<3%). This variation in the EBIC contrast may be related to the effect of boron and it is also indicated that the Sigma3{111} has the weakest gettering ability. When contaminated with Fe at 1100 degreesC, the EBIC contrasts of all the Sigma3 boundaries continued to increase and bright-denuded zones developed around the boundaries. The Sigma3 boundaries in the 1100 degreesC air-cooled mc-Si showed stronger EBIC contrasts and broader denuded zones than those in the 1100 degreesC quenched one. This phenomenon was explained in terms of the precipitation of Fe. The precipitation of Fe at grain boundaries (GBs) was affected by both the GB type and cooling rate, that is, Fe is easier to form precipitates onto the Sigma3{110} and Sigma3{112} boundaries during slow cooling. (C) 2005 American Institute of Physics.