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摘要
Titanium thin films deposited at various polar incidence angles by electron-beam evaporation are investigated by electron microscopy and X-ray diffraction pole-figures. The resulting film morphology and texture are shown to be strongly affected by the vapor flux direction. At normal incidence deposition angle, a fiber texture forms, with the c-axis of Ti crystallites aligned parallel to the surface normal with random in-plane (azimuthal) orientation. At off-normal deposition angles, porous morphologies with inclined micro-columns form. The texture of these films is an inclined fiber texture, where the texture tilt angle increases with increasing deposition angle. Biaxial texture is observed for films grown at polar incidence angles larger than 60 degrees. The micro-column tilt axis, and the c-axis of the crystallites, both lie in the deposition plane but at different polar angles; the mechanism behind micro-column tilt is due to the shadowing effect, whereas the fiber texture tilt angle and the biaxial texture orientations of the films result from evolutionary crystal growth, determined by the kinetic growth habits of crystallites. Changes in the morphology of Ti films deposited at a vapor incidence angle of 84 degrees and nominal thickness of 3 mu m at substrate temperatures corresponding to homologous temperatures of 0.15, 0.4, and 0.5 are studied, and compared to the Mukherjee and Gall structure zone model, proposed for high temperature glancing angle deposition. The observed morphology changes are consistent with their model of competition between shadowing length and adatom diffusion length. All the films were grown with homologous temperature lower than 0.5, and formed porous and inclined micro-column morphology, resulting from the dominance of shadowing over adatom surface diffusion.
- 出版日期2017-4-1
