VELOCITY OF GRAIN-BOUNDARY DISLOCATIONS IN A SIGMA = 9 BICRYSTAL OF SILICON

The velocity of DSC grain-boundary dislocations, with Burgers vector b(g) = 1/18[411BAR], is measured for temperatures ranging from 823 to 1023 K and stresses ranging from 10 to 30 MPa, in silicon SIGMA = 9 bicrystals. Screw segments are heavily kinked and much faster than edge ones, parallel to the [011] tilt axis of the bicrystals, which look very rigid. The apparent activation energy for the glide of fast screw segments is almost-equal-to 1.3 eV and the stress exponent m almost-equal-to 2.5. Results are discussed in terms of the kink-pair model and estimates of kink formation and migration energies, based on the core structures of kinks, satisfactorily account for the observed anisotropy of DSC dislocation motion.