The carrier recombination activity and structural properties of small-angle grain boundaries in multicrystalline Si were systematically investigated by electron-beam-induced current and transmission electron microscopy. At 300K, small-angle grain boundaries with a tilt angle of 0 to 10° generally exhibited a weak electron-beam-induced current contrast (0 to 10%) with the maximum contrast appearing at 2°, while some special small-angle boundaries with a tilt angle of 2 to 3° exhibited particularly strong contrast (∼30%). At a low temperature (100K), all of the small-angle boundaries exhibited a strong electron-beam-induced current contrast, in spite of the tilt angle. Possible explanations for the variation of the electron-beam-induced current contrast were explained in terms of the interaction and reconstruction of the boundary dislocations. When decorated with a metal impurity such as Fe, the boundaries exhibited much stronger electron-beam-induced current contrast than did large-angle boundaries; indicating that small-angle boundaries were effective gettering sites for impurities, due to their particular boundary dislocation structures.

Carrier Recombination Activity and Structural Properties of Small-Angle Grain Boundaries in Multicrystalline Silicon. J.Chen, T.Sekiguchi: Japanese Journal of Applied Physics, 2007, 46, 6489-97