Effect of Ge doping on the kinetics of iron–boron pair association and dissociation in photovoltaic silicon

Influence of germanium doping on the performance of high-performance multi-crystalline silicon

“…In the two kinds of ingots, the concentrations of Fe and B were the same in the silicon melt. X. Zhu et al [14] reported the interstitial iron in the Ge-doped silicon had a higher diffusion barrier than that in the undoped silicon and an extra activation energy of about 0.1-0.6 eV was necessary for the interstitial iron diffusion in the Ge-doped silicon. Ge doping in the mc-Si could reduce the probability of the combination of interstitial iron atoms and boron atoms through increasing the diffusion barrier of the interstitial iron in silicon, thus lowered the FeB complexes concentration.…”

“…But the electrical activity of FeB complexes was stronger than that of Ge-Fe complexes [20] and FeB complexes could be a stronger recombination center that leaded to a bigger influence on the minority carrier lifetime than Ge-Fe complexes. Moreover, because Ge doping could increase the diffusion barrier of interstitial iron [14] and reduce the amount of FeB complexes in the Ge-doped mc-Si ingot, Ge doping could improve the minority carrier lifetime of the mc-Si wafers. Furthermore, S. Wu et al [21] reported that FeB complexes were responsible for the lower minority carrier lifetime regions (red-zone) in conventional mc-Si ingots.…”