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

We have investigated the kinetics behaviors of iron–boron pair generation in photovoltaic Czochralski silicon with germanium doping in this paper. It is found that the activation energies of iron–boron pair association and dissociation in germanium-doped silicon are 0.67 and 1.26 eV, respectively, both larger than those in conventional CZ silicon. The pre-exponential factors are also increased by one order of magnitude. Experimental results and theoretical calculations both suggest that germanium can not only improve the diffusion barrier of iron, but also increase the capture radius of boron for iron.

► We have investigated the behaviors of FeB pairs in Ge-doped Czochralski silicon. ► Determined the characteristic of the reaction of FeB pair in GCZ silicon. ► Compared to CZ silicon, the characteristic value in GCZ silicon increased. ► Ge doping increases the diffusion barrier of interstitial Fe in silicon. ► DFT was induced to calculation the diffusion barrier of Fe and Gex–B complex.