OPTICAL MEASUREMENT OF EFFECTIVE RECOMBINATION LIFETIME IN SILICON EPITAXIAL LAYERS

In this letter we present a novel all-optical pump-probe technique for the measurement of effective recombination lifetime in silicon epitax ial layers. The procedure is based on the measurement of the variation of the attenuation coefficient due to optically injected free carrier s of a planar dielectric waveguide defined by the epitaxial layer clad ded between the substrate and the air. Perturbation theory is used to take into account nonuniform refractive index distribution due to nonz ero surface recombination. The measurement technique is validated by b oth numerical simulation and experimental results. (C) 1997 American I nstitute of Physics.