Correlation between residual strain and electrically active grain boundaries in multicrystalline silicon

We report the correlation between residual strain and electrically active grain boundaries (GBs) in multicrystalline silicon. The former concerns the process yield, and the latter affects the solar cell efficiency. The distribution of strain was imaged by scanning infrared polariscope, and the electrically active GBs were characterized by electron-beam-induced current. Large strain was detected near multitwin boundaries and small-angle GBs. The multitwin boundaries are electrically inactive, while small-angle GBs act as strong recombination centers. It indicates that the electrical activities of GBs are not directly related to the residual strain.