Interaction between Metal Impurities and Small-Angle Grain Boundaries on Recombination Properties in Multicrystalline Silicon for Solar Cells

Recombination properties at small-angle grain boundaries (SA-GBs) in multicrystalline silicon were evaluated. After Fe contamination, the electron-beam-induced current (EBIC) contrast at most SA-GBs became stronger, especially at >1.5 degrees. After Al gettering, EBIC contrast of most <1.5 degrees SA-GBs became as weak as before contamination. Then, some EBIC contrast of >1.5 degrees SA-GBs showed comparable contrast before gettering. In addition, there were SA-GBs which have different recombination properties even with the same misorientation angle. Between these SA-GBs, there were differences in the rotation axis, boundary direction, and existence of defects. The associativity of metals might be affected by the existence of defects caused by these differences. (C) 2012 The Japan Society of Applied Physics