In this work the influence on the gettering efficiency of varying cooling down ramps following aphosphorus-emitter-diffusion in a high-efficiency solar cell process is investigated. A hold-time ramp is applied atlow temperature where the emitter sheet resistance remains nearly unchanged and recombination active defects arestill mobile. We observed a significant enhancement of the effective minority carrier lifetime measured by the CarrierDensity Imaging (CDI) and Quasi Steady State Photoconductance (QSSPC) methods. This improvement is explainedby an increased diffusion of metal impurities into the gettering layer and by formation or growth of precipitates dueto a lower solubility of impurities in silicon at low temperatures.
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