Quantifying the effect of metal-rich precipitates on minority carrier diffusion length in multicrystalline silicon using synchrotron-based spectrally resolved x-ray beam-induced current

Synchrotron-based, spectrally resolved x-ray beam-induced current (SR-XBIC) is introduced as a technique to locally measure the minority carrier diffusion length in semiconductor devices. Equivalence with well-established diffusion length measurement techniques is demonstrated. The strength of SR-XBIC is that it can be combined in situ with other synchrotron-based analytical techniques, such as x-ray fluorescence microscopy ($\mu$ -XRF) and x-ray absorption microspectroscopy ($\mu$ -XAS), yielding information about the distribution, elemental composition, chemical nature, and effect on minority carrier diffusion length of individual transition metal species in multicrystalline silicon. SR-XBIC, $\mu$ -XRF, and $\mu$ -XAS measurements were performed on intentionally contaminated multicrystalline silicon, revealing a strong correlation between local concentrations of copper and nickel silicide precipitates and a decrease of minority carrier diffusion length. In addition, the reduction of minority carrier diffusion length due to submicron-sized ${\mathrm{Cu}}_3\mathrm{Si}$ and ${\mathrm{NiSi}}_2$ precipitates could be decoupled from the influence of homogeneously distributed nanoprecipitates and point defects.