Analysis of simultaneous boron and phosphorus diffusion gettering in silicon

We studied the simultaneous phosphorus and boron diffusion gettering (BDG) of iron in silicon by physical modeling. We present improvements to the previously used models for BDG and phosphorus diffusion gettering (PDG). We show that the improved model is suitable for analyzing the gettering efficiency in advanced solar cell structures with phosphorus doped (n+) and boron doped (p+) layers by comparing simulations with experimental results. The simulations indicate that during a low temperature step with high iron concentration, an additional p+ layer reduces the time needed for an effective gettering, whereas under low supersaturation segregation to the n+ layer is the dominating gettering mechanism.