For multicrystalline silicon, the principal understanding of gettering and other high temperatureprocesses is important for the optimisation of the solar cell performance. We studied this issue by examining theminority carrier density distribution before and after thermal oxidation with spatially resolved and injectiondependent lifetime methods. Experiments with different temperature ramps and times were done on two differentstarting materials. On pre-gettered material, results led to the hypothesis, that grain boundaries decorated withprecipitates emit interstitial iron atoms into their vicinity. Simulations strongly supported this theory of out-diffusion.On the material without pre-gettering more processes go on simultaneously. Out-diffusion could be found again, butmostly superimposed by other processes, allocated to surface gettering or clustering.
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