NEW RESULTS ON DISLOCATION TRANSMISSION BY GRAIN BOUNDARIES IN ELEMENTAL SEMICONDUCTORS

HVEM in situ straining experiments on Si and Ge bicrystals show that dislocations can be transmitted across high-angle grain boundaries even when their Burgers vector is not a lattice vector of the second grain, provided that sufficient stress concentrations arise at pile-up tips. Transmitted dislocations appear as Shockley partials, before they eventually recombine to form perfect dislocations. Repeated transmission of several similar dislocations from one pile-up is possible when the interface can be cleared of residual dislocations, which can sometimes be obtained by activating new slip systems