16:00 〜 18:00
▲ [9p-PB6-1] Phosphorus Gettering of Impurities for p-type PERC solar cells
キーワード：gettering
This paper shows a room for improving the performance of p-type passivated emitter and rear cells (PERCs) using the method of phosphorus (P) gettering of impurities at low-temperature annealing. As a result, a significant positive P gettering effect was found, as can be seen by an increase in lifetime with the gettering time increased. The results for the measured I-V parameters of the 2 h gettered PERCs revealed an increase in the open-circuit voltage (Voc) and short-circuit current density (Jsc) values with an increase in the gettering time, and the change in the fill factor (FF) was negligible. The internal quantum efficiency (IQE) of the 2 h gettered PERC shows a notable improvement for both short- and long-wavelength photons, indicating better quality of Si bulk as well as the surface passivaiton. A possible reason can be explained by the increased collection of dissolved impurities at P-gettered layers during low-temperature annealing. This low-temperature annealing should provide sufficient thermal energy for fast diffusing impurities in the bulk releasing towards P-diffused layer (external gettering). The slow diffusing impurities can internally gettering at the defects and/or nearby precipitates, leading to the reduction in the recombination activity per atom. These results further confirmed the benefit of P gettering at low-temperature annealing in order to improve the electrical properties and yield of PERC solar cells.