ANALYSIS OF GRAIN-BOUNDARY DISLOCATIONS BY LARGE-ANGLE CONVERGENT-BEAM ELECTRON-DIFFRACTION

Large angle convergent beam electron diffraction (LACBED) is used to a nalyse secondary dislocations in Sigma 3 and Sigma 9 grain boundaries in silicon. By selecting reflections from crystal planes common to the adjoining grains, LACBED images are insensitive to the boundaries exc ept where dislocations are present. The dislocation images are closely similar to those for dislocations in single crystals and can be analy sed by standard Cherns-Preston rules. It is shown that, for both bound aries, sufficient common reflections can be selected for a complete an alysis, and that dislocations can be analysed assuming integer values of g . b, implying that the Burgers vectors are Displacement Shift Com plete (DSC) lattice vectors. For both Sigma 3 and Sigma 9 boundaries, DSC dislocations are identified which are specific to these boundaries . The experimental conditions for the analysis of grain boundaries are explained, and the extension of the method to other coincidence bound aries is discussed.