High resolution electron microscopy of dissociated dislocations in silicon with a normal-incident electron beam

Abstract

Lattice image simulations appropriate to high resolution electron microscopy (HREM) imaging conditions have been produced for partial dislocations in Si under the condition that the electron beam is parallel to the normal to the stacking fault plane. It is shown that the positions of partial dislocations can be determined by the difference in the lattice image between the faulted and unfaulted regions; hence the existence of kinks can be resolved under appropriate conditions. Image simulations have also been made for reconstructed 90°- and 30°-partial dislocations. The results show that the reconstruction may be detected by HREM for the 30° partial but not for the 90° partial. HREM experiments on dislocations in Si introduced by plastic deformation reveal that: (i) the positions of partial dislocations can be determined for thin samples, (ii) 30° and 90° partials are easily distinguishable, (iii) high density kinks are observed, but it is concluded that these are produced, during observation, by electron beam irradiation, and (iv) no evidence has been obtained for the reconstruction of 30°-partial dislocation.