Determining the minority carrier lifetime in epitaxial silicon layers by micro-wave-detected photoconductivity measurements

Measurements of effective lifetimes on epitaxial silicon thin-film material have been carried out. Two different methods were used for this purpose: one is the well established Microwave-Detected Photoconductivity Decay (µPCD) method as commercially available from Semilab, and second the more recent Microwave-Detected Photoconductivity (MDP) method introduced by Freiberg Instruments. Both methods are critically analyzed and compared in regard to their applicability in the sector of epitaxial silicon layers. The investigation includes a modeling of the expected measurement signal for both measurement conditions. The results, obtained from a large number of lifetime samples investigated in this study and consisting of different qualities of the silicon substrate as well as different qualities of the epitaxial layer, support the conclusion that both of the above mentioned methods may be used to determine the effective lifetime of a silicon thin-film sample.