Gettering Efficacy of an APCVD Glasses Based Stacked Co-Diffusion for Bifacial mc-Si PERT Solar Cells

Gettering of impurities is an important task in p-type mc-Si solar cell production. Phosphorus diffusion via POCl3 is currently the most common way to achieve this. We report about the gettering efficacy of a co-diffusion in which POCl3 is not used. Phosphorus and boron containing glasses are both deposited prior to the diffusion via atmospheric pressure chemical vapor deposition (APCVD). The presented APCVD glasses based co-diffusion allows a loading without spacing and therefore has the potential for a very high throughput. As we demonstrate in this work, the overall gettering efficacy in different kinds of stacks is similar to the gettering efficacy in non-stacked APCVD glasses based diffusions. The reduction of interstitial iron in the analyzed lifetime samples is ascribed to phosphorus diffusion gettering and works in stacks just as well.