Behavior of nickel silicide in multi-crystalline silicon for solar cells

We investigated the behavior of nickel and its silicide at grain boundaries in multi-crystalline silicon for solar cells. The micro X-ray fluorescence spectrometer (μ-XRF) mapping, X-ray absorption near edge structure (XANES), UV-Raman spectroscopy mapping and transmission electron microscopy (TEM) were used for the evaluations. The nickel precipitation was detected only at random grain boundaries in the sample without annealing. On the other hand, the nickel precipitation was concentrated not only at random but also at some Σ9 grain boundaries after annealing process. In addition, it was confirmed the stress disappearance and the atomic rearrangement at Σ9 grain boundaries with the nickel precipitation. We consider that the crystalline structure reconstruction at grain boundary occurred due to the nickel silicide formation by the annealing process.