Heavily doped Si:P emitters of crystalline Si solar cells: Recombination due to phosphorus precipitation

The measured saturation current density J(0e) of heavily phosphorus-doped emitters of crystalline Si solar cells is analysed by means of sophisticated numerical device modelling. It is concluded that Shockley-Read-Hall (SRH) recombination exceeds Auger recombination significantly; it is caused by inactive phosphorus. This explains the large discrepancies be-tween measured and simulated J(0e) values, observed persistently over the last two decades in industrially fabricated Si solar cells. As a consequence, the heavily phosphorus-diffused emitters still bear a significant potential to contribute to higher Si solar cell efficiency levels, if the amount of inactive phosphorus can be reduced.