PESC电池扩散工艺的改进及分析

On Improvement in the Diffusion for the PESC Solar Cell

由于硅单晶质量的提高及背表面场和减反射膜技术的应用,电池的短路电流已接近理论极限值,因此其性能的改进就取决于发射区的优化.本文论述了一种改进的扩散工艺——二次扩散工艺.其主要特点是提高氧化温度,利用氧化过程的高温改善发射区杂质分布,从而减少“死层”的影响.文中分析并计算了二次扩散(氧化)后的杂质分布和结深的变化,并讨论了二次扩散对发射区少于复合的影响及工艺条件对发射区各参数的影响.

A two-step diffusion is proposed for the improvement in the diffusion process for the PESC solar cell. The specific feature of the new process consists in increasing the oxidation temperature after phosphorus diffusion. The emitter dopant profile and the minority carrier recombnation in different emitters in two-step diffusion and the diffusion process commonly used have been analyzed and compared. Some experimental results are given. The analysis shows that by two-step diffusion Jo can be reduced and Voc is increased. If the two-step diffusion is used together with the surface passivated process, the cell performance will be even better improved.