Glancing angle deposition to control microstructure and roughness of chromium thin films

Glancing angle deposition (GLAD) was used to sculpt chromium thin films sputter deposited by dc magnetron sputtering into the desired zigzag microstructure. The flux angle of incident species α was systematically varied from 0 to 50° and periodically changed from α to −α. The total film thickness was kept constant at 1 μm and the number of periods ranged from 0.5 to 10. In order to improve the film adhesion, a substrate heating (350 °C) was added during the sputtering. Our results show that the zigzag microstructure of chromium thin films influences the microstructure and the surface properties of the coatings. The relationships between the Ra roughness, the flux angle and the number of periods were successfully demonstrated. This allows the deposition of films with controlled roughness. It was shown that the regularity of the surface morphology is improved for the flux angles α > 20°. Microstructure of the films was investigated by SEM, AFM and X-ray diffraction and the mechanical properties were determined by nanoindentation.