Dissolution of electrically inactive phosphorus by low temperature annealing
In this study we investigate the dissolution of electrically inactive phosphorus complexes by low temperature annealing after the POCl3 diffusion process. This has the immediate consequence that the existing near-surface emitter volume SRH recombination can be reduced. Thereby, a significant reduction of emitter saturation current density j0E is achieved without driving the emitter further into the silicon substrate. For short-term temperature treatments well below the POCl3 diffusion temperature, a reduction of up to -60 fA/cm2 has been achieved. This study increases our understanding of the formation and dissolution of electrically inactive phosphorus complexes during post-annealing processes.
Improvement of industrial phosphorus diffused emitters and impact on solar cell efficiencies
In this study, we investigate the importance of the minority carrier lifetime (rp0) and surface recombination velocity (SRV) of industrial n-type emitters in improving emitter performance and improving solar cell efficiency. When emitters with higher τp0 values are applied to Al-BSF and PERC solar cells separately, they show slightly different responses to the increase in τp0. Simulation results indicate that PERC solar cells receive a larger efficiency enhancement with the same increase in τp0 than that for Al-BSF cells. This is due to the fact that emitter recombination can be a major contributor to efficiency loss for solar cell structures like PERC where the rear surface is well passivated by dielectric stacks. Additionally, LDSE cells have a stronger dependence on the surface passivation quality, especially for the PERC structure.
Modeling phosphorus diffusion gettering of iron in single crystal silicon
We propose a quantitative model for phosphorus diffusion gettering (PDG) of iron in silicon, which is based on a special fitting procedure to experimental data. We discuss the possibilities of the underlying physics of the segregation coefficient. Finally, we show that the proposed PDG model allows quantitative analysis of gettering efficiency of iron at various processing conditions.