Large Area High Efficient Back-Junction Back-Contact Silicon Solar Cells with Industrial Process

Abstract

High efficiency back-junction back-contact silicon solar cells using 6” n-type Cz material and an industrial feasible process flow based on hybrid junction formations and all screen printed metallization are presented. The boron emitter and FSF/BSF were formed by diffusion technique with BCl3 precursor and PH3 ion-implantation respectively. The interdigitated pattern was formed by single dielectric masking and opening for ion-implantation. Both of front and rear sides were passivated by silicon oxide and nitride stack. Excellent current collection was achieved due to an optimized FSF and reduced electrical shading effect. Also, the FF had been improved by the study of the metal contact ratio and pitch effect. The large area cell efficiency up to 21.6% was realized and zero LID had been proved.