Tilting angle of nanocolumnar films fabricated by oblique angle deposition

The tilting angle, β, of nanocolumns during oblique angle deposition (OAD) as a function of vapor incident angle, θ, has been investigated through both literature survey and systematic experiments. Most experimental data cannot be fit by either the tangent or cosine rule and show strong material dependence. The material-dependent fan angle, φ, can be extracted using the fan-out model proposed by Tanto et al. [J. Appl. Phys. 108, 026107 (2010)]. This fan angle, φ, depends closely on the melting temperature for single element materials, the heat of formation for compound materials, lattice structure, and the complexity of the materials, and is a critical parameter in understanding the fundamental growth mechanism of OAD.