Cathodoluminescence assessment of annealed silicon and a novel technique for estimating minority carrier lifetime in silicon

The effect of low-temperature anneals (≤500 °C) on Cz–Si minority carrier lifetime has been investigated using near-band-edge cathodoluminescence (CL). The low-temperature anneals are intended to produce efficient gettering by taking advantage of the increasing supersaturation of impurities as temperatures are reduced. It is found that the anneals affect the CL efficiency through several different mechanisms and that annealing under “dirty” conditions does not introduce significant amounts of electrically active impurities into the material. In order to aid the interpretation of experimental results, modelling of the effect of different sample parameters on CL is carried out. Using this theoretical work, an experimental method of measuring minority carrier lifetime using CL which is independent of surface recombination is developed.