Electron-beam-induced current study of grain boundaries in multicrystalline Si

Systematical studies on the intrinsic and extrinsic recombination activities of grain boundaries (GBs) in multicrystalline silicon (mc-Si) were reported by using temperature-dependent electron-beam-induced current (EBIC). EBIC results revealed that in the clean mc-Si, all the GBs exhibited weak EBIC contrasts at 300 K, suggesting their recombination strengths were weak and the energy levels were associated with shallow levels. The effect of impurity contamination was also evaluated by employing different contamination levels of Fe. The EBIC contrasts of GBs were enhanced after Fe contamination and showed a strong dependence on both the GB character and contamination level. The impurity gettering abilities of GBs were as following, SA > R > high-Sigma > low-Sigma. SA GBs were found with the strongest impurity gettering ability and tended to be the most detrimental GBs. Finally, the effect of H-passivation on different GBs with or without contamination was evaluated.