
131Biosensing Based on Surface-Enhanced Raman Spectroscopy
6.3.1.2.5 Oblique-Angle Deposition and Glancing-Angle Deposition
Oblique-angle deposition (OAD) combines physical vapor deposition, such as electron beam
deposition, with steep substrate angles >75°, relative to the vapor source. Thin lms pro-
duced by PVD tend to have columnar or porous microstructures and tilting the substrate
at steep angles (>75°) relative to the substrate normal leads to geometrical shadowing
effects and the preferential growth of nanostructures [114]. As shown in Figure 6.9a,
atoms condense and diffuse on the substrate surface then form nuclei. The region behind ...