Identification Possibility of Metallic Impurities in p‐Type Silicon by Lifetime Measurement

Abstract

The prospect of the identification of metallic impurities in p‐type silicon has been studied using the photoconductive decay lifetime measurement technique at various high excitation levels (10¹¹ to 1.5 × 10¹³ photon/pulse). The excitation level dependence of the recombination lifetime shows unique characteristics for recombination centers attributed to Al, Cr, or Fe related levels. The unambiguous identification of iron and chromium is performed by the analysis of the excitation level dependence curves measured before and after a low temperature (180°C) thermal treatment. The calculation of the iron concentration in the presence of other recombination centers is discussed. Contrary to the low excitation case the determination of iron concentration from the lifetime measured at a high excitation level requires only one correlation constant for a wide range of resistivity.