HIGH MINORITY-CARRIER LIFETIME IN PHOSPHORUS-GETTERED MULTICRYSTALLINE SILICON

The electronic quality of multicrystalline material produced by direct ional solidification has been evaluated by means of photoconductance t echniques. Very high minority carrier lifetimes, in the vicinity of 20 0 mu s, have been measured in p-type 1.5 Omega cm material that had re ceived a phosphorus diffusion gettering treatment. The measurements co rrespond to an effective lifetime averaged over an area of 3 cm(2) tha t includes several grain boundaries and reflects the combined bulk, gr ain boundary and surface recombination mechanisms. The high lifetime ( 15 mu s) also obtained in low resistivity 0.2 Omega cm wafers has allo wed the fabrication of solar cells with an open-circuit voltage of 657 mV (AM1.5 G, 100 mW/cm(2), 25 degrees C), probably the highest ever r eported for multicrystalline silicon. (C) 1997 American Institute of P hysics.