The effect of the annealing ambient on the efficiency of the phosphorous gettering process for Czochralski (CZ) silicon wafers is investigated in this paper. Phosphorous is diffused from a POCl3 source at different temperatures into single-crystal p-type silicon wafers having a resistivity of around 1 ohm/cm. This is followed by an additional heat treatment in either oxidizing (wet and dry oxide) or in inert (argon) ambient. The laser microwave photoconductivity decay method is used to monitor the changes in the minority carrier lifetime after the phosphorous diffusion and the subsequent,annealing. Furthermore, solar cells are fabricated on the treated samples in order to correlate the lifetime measurements with the illuminated I-V characteristics of the cells. (C) 2000 Elsevier Science Ltd. All rights reserved.