AbstractWe discuss an approach to iron concentration determination in silicon, based on wafer-scale surface photovoltage measurement of the minority carrier diffusion length in the millimeter range. The approach combines two novel aspects: it overcomes the diffusion length to wafer thickness ratio limitation of previous SPV methods, and it employs iron separation from other recombination centers using rapid photo-dissociation of iron-boron pairs. The wafer thickness limitation was eliminated by using the correct theoretical SPV wavelength dependence instead of simplified asymptotic diffusion length form adopted in all previous treatments and valid only for diffusion lengths much shorter than the wafer thickness. Photo-dissociation of Fe-B pairs and measurement of the corresponding decrease of the L value (caused by creation of iron intersticials) enables iron detection in typical silicon wafers in times of seconds with a sensitivity in the low 108 atoms/cm3 range.