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This paper reports the results of a systematic study on the kinetics of dissociation and formation of iron-boron (FeB) pairs in boron-doped Czochralski silicon after phosphorus implantation gettering of iron at different temperatures. The aim of this study is threefold: (i) investigation of the dissociation kinetics of the FeB pairs by a standardized illumination as a function of the iron concentration after gettering process, (ii) study of the kinetics of their association, and (iii) extraction of the characteristic parameters of these two phenomena for gettered samples, in particular the effective time constants of dissociation and association as well as the constant of material, which describes the dissociation rate well in the absence of other recombination channels.

Control of detrimental metal impurities is crucial to silicon solar cell performance. Traditional silicon solar cell emitters are diffused in an infinite-source regime and are known to cause strong point defect segregation towards the emitter and thus enhance bulk minority carrier diffusion length. With the advent of ion-implantation and chemical vapor deposition (CVD) glasses, finite-source diffused emitters are attracting interest. This contribution aims to increase their adoption by elucidating the dominant gettering mechanisms present in finite-source diffused emitters. Our findings indicate that infinite-source diffusion is critical for effective segregation gettering, but that high enough surface phosphorus concentration can activate segregation gettering via finite-source diffusion as well. In the case of ionimplanted emitters, the traditional segregation gettering may be considerably enhanced by impurity precipitation in the implanted layer.

We have investigated in this work the effect of the temperature profile during homogeneous phosphorous diffusion gettering (PDG) on multicrystalline (mc-Si) silicon p-type wafers destined for photovoltaic solar cells. Temperatures were varied from 800 • C due probably to a partial dissolution of the metallic precipitates, especially at the grain boundaries and in the dislocations vicinity. The related τCr-Impurity lifetime value of about 8.5 µs is extracted, which is the result of interstitial Cri or CriBs pairs, proving their strongest recombination activity in silicon.

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