ANNEALING-INDUCED CHANGES OF RECOMBINATION IN CAST POLYCRYSTALLINE SILICON

The effect of annealing on recombination properties of polycrystalline solar-cell silicon was investigated by EBIC, using minority-carrier diffusion length and defect contrast as measure of the occurring changes. Rapid thermal annealing was found to reduce the activity at dislocations in the grains and improved the diffusion length markedly, whereas conventional annealing in ampuls led to a degradation of the material. Transmission electron microscopy was applied to study the structure of the different recombination-active defects.