Effects of oblique angle deposition on surface wettability of Sn metal thin films

Oblique angle deposition is a powerful technique to tailor the physical properties of the films because it results in significant modification of grain growth and surface morphology. The present study reports the effects of deposition angle on the hydrophobicity and surface morphology of Sn metal thin films. The significant changes in the topography of the films have been observed with the change in the deposition angle. X-ray diffraction studies show that films have highly oriented (100) tetragonal crystal structure and crystallite size for obliquely deposited (45 nm) film is smaller as compared to that of the normally deposited film (50 nm). The FESEM and AFM studies show that the grain size and the surface roughness of obliquely deposited film decrease as compared to that of the normally deposited film. The obliquely deposited film is found to be hydrophobic in nature with an average contact angle of 95 ± 4° whereas the average contact angle for the normally deposited film is 89 ± 4°. The results of this study reflect that the wettability of the films can be easily tuned by varying the deposition angle.