Improvement of phosphorus gettered multicrystalline silicon wafers by aluminum treatment

In thin multicrystalline silicon cells (d<200 mm), previously improved by phosphorus gettering, a back surface field (BSF) is necessary. The BSF could be obtained by aluminum alloying and diffusion. Samples gettered for a long time are markedly improved during the annealing of the Si-Al structure at 800 degrees C for 30 min, and L/sub n/ overpass the thickness of the samples. Although the influence of an additional gettering effect is not precluded, it is emphasized that the aluminum treatment results in the hydrogenation of the wafer.<
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