HIGH-RESOLUTION ELECTRON-MICROSCOPY OF DISSOCIATED DISLOCATIONS IN SILICON WITH A NORMAL-INCIDENT ELECTRON-BEAM

Lattice image simulations appropriate to high resolution electron micr oscopy (HREM) imaging conditions have been produced for partial disloc ations in Si under the condition that the electron beam is parallel to the normal to the stacking fault plane. It is shown that the position s of partial dislocations can be determined by the difference in the l attice image between the faulted and unfaulted regions; hence the exis tence of kinks can be resolved under appropriate conditions. Image sim ulations have also been made for reconstructed 90 degrees- and 30 degr ees-partial dislocations. The results show that the reconstruction may be detected by HREM for the 30 degrees partial but not for the 90 deg rees partial. HREM experiments on dislocations in Si introduced by pla stic deformation reveal that: (i) the positions of partial dislocation s can be determined for thin samples, (ii) 30 degrees and 90 degrees p artials are easily distinguishable, (iii) high density kinks are obser ved, but it is concluded that these are produced, during observation, by electron beam irradiation, and (iv) no evidence has been obtained f or the reconstruction of 30 degrees-partial dislocation.