A thermal dynamical boron getter (pp+ getter) in Fe-contaminated mass production of the boron diffused n+pp+ BSF bifacial silicon solar cells

Thermal dynamical treatments for improving the lifetime of the p base of n+pp+ BSF bifacial silicon solar cells have been demonstrated using iron behavior parameters called pp+ getter. The SIMS for the wafers in mass production showed a precipitated high concentration of the iron region near the surface of the boron diffusion layer, and the phosphorus diffusion layer respectively. A high temperature treatment is supposed to increases iron in the p base by diffusing interstitially from the precipitated region, and low temperature treatment decreases the iron over the solubility diffusing to the precipitated region. So, the last thermal treatment needs a long time and the low temperature enough for improving the lifetime. The simulations and examinations on the changes of the lifetime through the cell process showed good consistency.