Improvement of silicon nitride solar cells after thermal processing gettering or passivation

Experiments carried out by RF glow discharge on phosphorus-diffused N/sup +/P junctions have shown that hydrogen neutralization only takes place in the 300-400 degrees C temperature range. The observed increase of the bulk diffusion length L/sub D/ is completely lost if post annealing is performed at temperatures higher than the stability of hydrogen bonds with defects or impurities (i.e., 450-500 degrees C). However, some L/sub D/ improvement reappears for temperatures higher than 650 degrees C which is probably correlated with an enhancement of the phosphorus gettering.<
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