Evaluation of Effective Carrier Lifetime in Epitaxial Silicon Layers

摘要

This paper presents an exact solution for the effective recombination lifetime of excess carriers in epitaxial silicon wafers derived from the current continuity equation. The solution is valid for arbitrary doping levels both in the epitaxial layer and in the substrate, as the built-in potential is taken into account in the model. We have also derived an analytical approximate expression for the effective lifetime. The results indicate that the effective lifetime is not only a function of the bulk lifetime values in the epitaxial layer and in the substrate, but also a function of the layer thicknesses and doping levels. The possibility for extracting recombination parameters in the epitaxial layer from the measured effective lifetime is discussed.