多孔硅对多晶硅太阳电池中缺陷和杂质的吸除效应

GETTERING OF DEFECTS IN POLYCRYSTALLINE SILICON SOLAR CELLS BY POROUS SILICON

吸杂是减少硅中杂质和缺陷,提高多晶硅太阳电池效率的一种有效手段。本文比较了用三种吸杂方式对多晶硅进行处理的结果和影响:多孔硅吸杂,磷吸杂,多孔硅结合磷吸杂。三种吸杂方式都能明显提高多晶硅的少子寿命。在此基础上研究了多孔硅吸杂的工艺,发现多孔硅吸杂的效果随退火的温度和时间影响比较大,在800℃氮气气氛下退火3h,多晶硅的少子寿命能由原来的1 4μs提高到25 6μs。相比之下,多孔硅吸杂工艺简单,更适合工业生产。

Polycrystalline silicon is the main material of commercial solar cells, but the defects and impurities cause the solar cell with low efficiency. Three ways of gettering of polycrystalline silicon are compared: gettered by porous silicon, gettered by heavy phosphor diffusion and gettered by porous silicon combined with heavy phosphorous diffusion. All these three ways can improve the minority carrier lifetime effectively. Moreover, the parameters of porous silicon getteing were invesigated. The minority carrier lifetime increased from 1.4μs to 25.6μs when the annealing temperature was 800℃ for 3 hours. Compared with the other two ways of gettering, porous silicon gettering was simple and more suitable for the industry of solar cells.