Effect of germanium on the kinetics of boron-oxygen defect generation and dissociation in Czochralski silicon

We have investigated the kinetics of boron-oxygen (B-O) defect generation and dissociation in germanium-doped Czochralski (GCZ) silicon. It is found that the activation energies for the B-O defect generation and dissociation in the GCZ silicon are around 0.63 eV and 1.52 eV, respectively, both larger than those in the conventional CZ silicon. The corresponding pre-exponential factors also are enhanced by two orders of magnitude due to Ge doping. It is believed that the Ge cannot only cause a higher energy barrier for oxygen-dimer (O-2i) diffusion, due to its modulation on the crystal field in silicon lattice but also enhance the capture cross-section of B-s for O-2i, as a result of Ge-B complex formation, as predicted by first-principle calculation. These results are significant for us to understand the mechanism of Ge influencing on the B-O defects in CZ silicon. (C) 2010 American Institute of Physics. [doi: 10.1063/1.3505499]