Nucleation controlled phase selection in vanadium/amorphous silicon multilayer thin films

Cross-sectional transmission electron microscopy, isothermal and constant-heating-rate calorimetry, and thin film x-ray diffraction have been used to investigate amorphous and crystalline silicide phase formation in vanadium/amorphous silicon multilayer thin films. The atomic concentration ratio of the films was one V atom to two Si atoms and the modulation period was either 14 or 50 nm. The first silicide phase to form at the vanadium/amorphous silicon interface was amorphous-vanadium-silicide. Heating to temperatures above 750 K caused crystalline VSi₂ to form at the amorphous-vanadium-sihcide/amorphous silicon interface. Analysis of cross-sectional transmission electron microscopy and both isothermal and constant-scan-rate calorimetric data suggest that nucleation barriers control the formation of crystalline VSi₂.