Phase transformation and defect structures in thin-film TaSi2 produced by co-sputtering were investigated as a function of annealing temperature by transmission electron microscopy. Crystallization of amorphous TaSi2 thin films occurred at 400 °C without forming any metastable phases. Most of C40 TaSi2 crystallites contain planar faults parallel to (00•1) basal planes. Convergent-beam electron diffraction indicated that these planar faults were not simple stacking faults but were twin boundaries bounded by two adjacent enantiomorphically-related twin domains; i.e., domains belonging to the space groups P6222 (right-handed) and P6422 (left-handed) having the identical crystal orientation arrange alternatively separated by twin boundaries parallel to (00•1). The formation of these enantiomorphically-related domains in TaSi2 thin films with the hexagonal C40 structures was considered in comparison with the formation of twin-related domains in MoSi2 (the tetragonal C11b structure) and TiSi2 (the orthorhombic C54 structure) thin films. A new convergent-beam electron diffraction method was proposed for the identification of enantiomorphically-related crystals, in which asymmetry in the intensity of Bijvoet pairs of FOLZ disks in an experimental symmetrical zone-axis convergent-beam electron diffraction pattern was compared with that in a computer simulated convergent-beam electron diffraction pattern.

Defect Structures in TaSi2 Thin Films Produced by Co-Sputtering. H.Inui, A.Fujii, T.Hashimoto, K.Tanaka, M.Yamaguchi, K.Ishizuka: Acta Materialia, 2003, 51[8], 2285-96