Light Induced Plating of Silicon Solar Cells Using Boric Acid-Free Nickel Chemistry

A novel boric acid-free nickel plating chemistry has been developed to plate nickel onto silicon solar cells. This bath enables light induced plating (LIP) of nickel without the use of external rectification. The resulting deposit is low stress and has been shown to be an effective barrier to copper diffusion. Solar cells plated using this nickel bath demonstrate electrical, adhesion and reliability results similar to silver paste controls. In addition, these plated cells have lower contact resistance and higher metal conductivity than silver paste controls using similarly diffused wafers. The advantages of a boric acid-free nickel bath will be reviewed in detail.