| Oblique angle deposition technique combines a conventional physical vapor deposition system with a tilted and rotating substrate. The technique has attracted considerable attention recently due to its ability to generate novel three-dimensional (3D) nano-structures. By the shadowing effect, the incident flux of material that comes to the surface with an oblique angle is preferentially deposited onto the top of surface features with larger height values. This preferential growth dynamics give rise to the formation of self-assembled three-dimensional nano-structures such as nano-columns, nano-springs, and nano-balls. The process is simple in that within a single deposition step it is possible to obtain many novel nano-structures of current interest.; In this thesis, it is aimed to investigate the growth dynamics of oblique angle deposition in detail both experimentally and theoretically. The growth regimes studied covers the deposition times from very early stages of island growth to later stages of columnar structures.; It is shown that during the initial stages of oblique angle deposition, the island formation is enhanced through the shadowing effect, where the isolated islands are easier to form compared to normal incidence growth. Moreover, even in the absence of surface diffusion, we observe a quasi-periodic nature in the island-island correlation function. At the later stages of the growth, where the three-dimensional columnar structures start to form, the nano-columns deposited by oblique angle deposition also develops a quasi-periodic morphology which is not observed for continuous films deposited at normal incidence under similar deposition conditions. The formation of quasi-periodic nature is explained by a shadowing length effect that plays a similar role as the surface diffusion length in conventional morphology resulting from island formation. The shadowing length results from an effective capturing distance that covers the regions being shadowed by the surface feature.; In addition, it has been found that there is a scaling relationship for the evolution of isolated columnar width of various materials (Si, Co, Co, and W) with column length. The column width changes with column length according to a power law with the exponent p ∼ 0.28--0.34. It is argued that the growth exponent should cross over from 0.50 with pure shadowing and no surface diffusion to 0.31 with both shadowing and surface diffusion.; Finally, the effect of oblique angle flux on the formation of various crystal planes has been analyzed. The fabrication and growth mechanisms of single crystal beta-phase (100) oriented tungsten nano-columns have been presented. Sputter deposition at normal incidence produced only the thermodynamically stable bcc alpha-phase W(110) polycrystalline films. The formation of single crystal beta-W(100) nano-columns by the oblique angle deposition is explained by a combination of the shadowing effect and the difference in the adatom surface mobilities among different crystal planes. |
