Effect of gettered iron on recombination in diffused regions of crystalline silicon wafers

Crystalline silicon wafers, intentionally precontaminated with iron, were diffused with phosphorus and boron, and the recombination properties of the bulk and diffused regions extracted from injection-dependent carrier lifetime measurements. While the phosphorus diffusions were found to getter more than 99% of the iron from the bulk, the boron diffusions only extracted 65% in the best case. The presence of this gettered iron caused significant additional recombination in the boron diffused layers, while it had no measurable impact on the phosphorus diffused regions. This may be a consequence of the small capture cross section for holes of interstitial iron.