Silicon epitaxial layer recombination and generation lifetime characterization

We have made recombination and generation lifetime measurements on silicon p-epitaxial layers on p⁺ and on p-substrates. The recombination lifetimes are dominated by surface/interface recombination for layers only a few microns thick. By coupling measurements of p/p with those of p/p⁺ samples, it is possible to extract the epi-layer lifetime. For p/p⁺ samples, recombination lifetimes are poorly suited to characterize epi-layers. Generation lifetime measurements are eminently suitable for epi-layer characterization, since carrier generation occurs in the space-charge region confined to the epitaxial layer, and when coupled with corona charge/Kelvin probe, allow contact-less measurements.