EBIC Study on Metal Contamination at Intra Grain Defects in Multicrystalline Silicon for Solar Cells

摘要

Interactions between intra-grain defects and metal impurities in multicrystalline silicon (mc-Si) were evaluated. After metal contaminations, EBIC contrasts at > 1.5° SA-GBs were more enhanced than those at < 1.5° SA-GBs, and the order was Fe/1000 ℃ > Ni/1000 ℃ > Ni/600 ℃. These results might attribute to Fe atoms form deeper energy levels of recombination centers than Ni atoms and the gettering abilities at SA-GBs depend on the misorientation angles. Many dark spots were observed in EBIC images in the Ni/600 ℃. Since the dark spots corresponded to the etch pits, the dark spots might be dislocations decorated with Ni. The gettering abilities of SA-GBs depended on the misorientaion angles, and the recombination properties at SA-GBs and dark spots, such as small defects after metal contamination were different by annealing temperatures and the types of metal impurities.