Recombination in n- and p-Type Silicon Emitters Contaminated with Iron

Crystalline silicon wafers containing deliberately introduced Fe were subject to phosphorus and boron diffusions, in order to examine the effect of gettered Fe on the recombination properties of the diffused emitter regions. For the case of boron diffusions, the presence of gettered Fe caused increased recombination in the emitter region, while for phosphorus diffusions there was no noticeable effect. This occurred despite the fact that the boron diffusions were much less effective at gettering Fe from the wafer. The results can apparently be explained by the reduced recombination activity of the Fe-related centres in n-type silicon compared to p-type