Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
728899 | Materials Science in Semiconductor Processing | 2008 | 5 Pages |
Carrier lifetime limitation defects in polycrystalline silicon ribbons have been examined in samples with high oxygen and carbon content. Infrared spectroscopy showed that essentially all supersaturated oxygen impurities precipitated within 1 h annealing at over 800 °C. Preferential defect etching revealed that a much higher density of oxygen precipitates were generated in dislocation-free grains than in those highly dislocated (105–107 cm−2) ones. Correlated with electron-beam-induced current imaging, we found that oxygen precipitates are the dominant carrier recombination defects in dislocation-free grains, while dislocations are the lifetime killer for highly dislocated grains. It is suggested that eliminating dislocations alone will not improve the carrier lifetime, considering that a higher density of oxygen precipitates formed in the absence of dislocation-related heterogeneous nucleation sites will significantly degrade the carrier lifetime.