CARRIER INJECTION ENHANCED DISLOCATION GLIDE IN SILICON

In situ observations of dislocation motion in solar-grade polycrystalline silicon are performed in a high-voltage electron microscope. Compared to previous measurements in single-crystal silicon the dislocation Velocities are found to be enhanced, which may be due to a recombination enhancement owing to the excess carriers created by the electron beam. A detailed analysis reveals that the migration barrier was reduced by about 0.6 eV, which is consistent with earlier measurements proving the dislocation mobility to be enhanced by near bandgap illumination. However, while the so-called photoplastic effect was observed only at temperatures below 450 degrees C, here the cathode-plastic effect is evident up to 690 degrees C. It is proposed that the recombination enhancement of the dislocation motion is caused by recombination-assisted kink formation rather than by recombination-enhanced kink migration.