AUGER RECOMBINATION IN MODULATED PHOTOREFLECTANCE CHARACTERIZATION OF SILICON-WAFERS

We have used photoreflectance signal as a function of modulation frequency to characterize electronic transport properties in silicon wafers. Due to the high densities of free carriers generated in such an experiment, we propose a theoretical model which takes into account Auger recombination. This nonlinear recombination process is usually neglected in the interpretation of photothermal phenomena. Our experimental results, in good accordance with theoretical prediction, show that this nonlinear recombination process not only cannot be neglected, but can be the dominant recombination process for certain experimental configurations, particularly for modulation frequencies up to 100 Khz and pump power ranging from 1.5 kW/cm2 to 9 kW/cm2.