Characterization of High-Purity Silicon with the Photoconductivity Decay and Photoluminescence Analysis Techniques

Photoconductivity decay (PCD) and low-temperature photoluminescence (PL) techniques have been used to complementarily characterize float-zoned, high-purity silicon single crystals for microdefects and residual boron and phosphorous. The consequence of nonuniform carrier injection in PCD was examined by numerical calculations and measurements, and we found that it comes into effect when samplesize is larger than 10 times the minority carrier diffusion length. In high-purity, dislocation-free crystals, swirl defects dominate carrier recombination. Fast cooling of crystals from high temperature forms frozen-in defects that are effective Shockley-Read-Hall recombination centers. Fast cooling also changes PL peak heights, affecting boron and phosphorous measurement and resulting indifferent interpretations of shallow impurity line series to the existing multiple-bound-exciton-complexes model.