A comparative study of electronic transport properties of p-Si wafers intentionally contaminated with Fe was performed using infrared photothermal radiometry (PTR) and microwave photoconductance decay (µ-PCD). Strong correlations were found between PTR and µ-PCD lifetimes in a lightly contaminated wafer with no significant PTR transient behavior. The absolute PTR lifetime values were larger than the local averaged µ-PCD values, due to the different excitation wavelengths and probe depths. In a heavily contaminated wafer the µ-PCD and PTR lifetime correlation was poorer. PTR measurements were highly sensitive to Iron concentration, most likely due to the dependence of the bulk recombination lifetime on it. Rapid-scanned (non-steady-state) PTR images of the wafer surface exhibited strong correlations with both µ-PCD lifetime and Iron concentration images in both heavily and lightly contaminated wafers. For the lightly and uniformly contaminated wafer, PTR scanning imaging was found to be more sensitive to iron concentration and lifetime variations than µ-PCD images.

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Subject classification: 72.20.Jv; 73.40.Mr; S5.11 Laser infrared photothermal radiometry (PTR) was used as an analytical technique to measure the electronic transport parameters of p-Si wafers oxidized and thermally annealed under positive or negative external bias applied to the back surface. It was found that, following Fe contamination and recombination lifetime t e , degradation in the oxidation and thermal-anneal furnace, both polarities of the external field result in significant minority carrier lifetime improvement, as well as in strong changes in the front-surface recombination velocity S 1 , of the samples, compared to a zerobias annealed reference sample. A qualitative model involving the passivating action of positive mobile ions (protons) trapped at the oxide-Si interface was advanced to explain the relative relations S 1 (+) > S 1 (0) > S 1 (--) . The lifetime relations t e (+) > t e (--) > t e (0) obtained through both PTR and electrolytical metal tracer (ELYMAT) measurements were explained in terms of the relative abilities of positive and negative applied electric fields to prevent heavy metal ions from diffusing into the Si bulk and compromising the lifetime.

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