Laser-transferred niv-seed for the metallization of silicon heterojunction solar cells by Cu-plating

We present results about a laser-based method for the metallization of silicon heterojunction solar cells by Cu-plating. The method consists of first depositing a dielectric layer as plating mask onto the transparent conductive oxide (TCO) and then depositing a NiV seed layer onto the plating mask by laser induced forward transfer (LIFT). Afterwards, the seed layer is fired through the plating mask in a second laser step in order to form a contact to the TCO. By dividing the process into laser transfer and firing (LTF) each step can be optimized separately. The final metallization is produced by Cu-plating. A pulse plating process is applied to further reduce parasitic plating. Different dielectric layers are tested as plating masks for their resistance against parasitic plating. The combination of a 15 nm thick Al2O3 layer as plating mask in conjunction with pulse plating is completely free of parasitic plating. Finally an efficiency of 22.2% is reached outperforming the screen printed reference cells by 0.5%abs.