Electron Diffraction Analysis of the Pentagonal Arrangement of Grains Found in CVD Pure Ni Films

摘要

The structure of each crystal in the pentagon is fcc, as verified by diffraction patterns from individual grains. It is suggested that the large pentagonal regions observed were nucleated by small decahedral clusters of Ni atoms during the early stages of the deposition. However, for grains as large as those shown the body centered orthorhombic structure is not stable; at some point during the growth process the crystal structure reverted to the energetically preferred fcc. The relative orientation between the individual crystals, having been established by the decahedral nucleus, was preserved during growth. The 7.5 sup 0 mismatch was taken up evenly around the pentagon by the formation of dislocations and/or secondary twins at the boundaries. (ERA citation 11:038294)