On the use of a bias-light correction for trapping effects in photoconductance-based lifetime measurements of silicon

The effectiveness of a method for analytically reducing the effect of trapp ing centers on photoconductance-based recombination lifetime measurements i n silicon is examined. The correction method involves the use of a "bias-li ght" term to subtract out the underlying photoconductance due to the traps. The technique extends, by approximately an order of magnitude, the range o f carrier densities over which reasonably accurate (within 30%) measurement s of the recombination lifetime can be made. Guidelines for determining whi ch bias-light intensity will produce the best correction for solar grade mu lticrystalline silicon wafers, and the range over which it is valid, are de veloped for several practical cases. (C) 2001 American Institute of Physics .