Separate determination of the photoelectric parameters of n+-p(n)-p+ silicon structure base region by noncontact method based on measurements of quantum efficiency relationships at two wavelengths

In this work we calculated nomograms for separate determination of the nonequilibrium carrier lifetime for the illuminated p(n) local region and the carrier surface recombination rate using the measured intensity ratios. The calculations were performed at low injection for one dimensional case. The nomograms were calculated at 1064 and 808 nm wavelengths for various thicknesses of the n+-p(n)-p+ structures and various modulation frequencies. We found that the nomograms depend little if any on the modulation frequency if the nonequilibrium carrier lifetime is less than the modulation period. We also established that the nomograms of thin structures undergo essential shifts and changes in pattern if the diffusion time of the nonquilibrium carriers from the rear side of the structure to its face side becomes shorter than the nonequilibrium carrier lifetime. In this case the nomograms can only be used for determining the surface recombination rate of the nonquilibrium carriers at the rear side of the structure.