Sensitivity analysis for the determination of recombination parameters in Si wafers using harmonic carrier generation

Abstract

The sensitivity of a contactless measurement procedure to determine the minority-carrier recombination parameters in Si wafers is analyzed. The measurement is based on the harmonic generation of excess carriers, whose time dependence is measured either by μ-wave reflection or free-carrier absorption. Both the measurement equipment and the model used to extract the surface recombination velocity and the bulk carrier lifetime are introduced and the sensitivity of the parameter fit procedure is examined. The results of this uncertainty analysis are applied to typical experimental situations, e.g., bulk minority carrier lifetime measurement of a monocrystalline wafer with equal surfaces or a bulk minority carrier lifetime mapping done on an as-grown multicrystalline Si wafer before it obtained saw damage removal. The method proves to be very useful, if the interpretation of the results is carefully done and an appropriate experiment is chosen to produce the best possible results.