11. Ion Beam Sputtering Induced Glancing Angle Deposition

The method of ion beam sputtering under glancing angle conditions in combination with an additional rotation of the sample holder allows the growth of almost arbitrarily designed nano- and microstructures of all material classes on surfaces. The self-shadowing and the surface diffusion essentially govern the structure evolution. It is demonstrated that by varying the particle incidence angle, the temperature, azimuthal rotation frequency, and the beam divergence of the sputtered particles, a wide variety of nanostructure morphologies (e.g., slanted and vertical columns, screws, spirals, or zigzag columns) can be generated. Ballistic simulations are preferably used to simulate the growth of these structures. It can be shown that two basic alternatives of ballistic simulations, off-lattice simulations and on-lattice simulations, are available to successfully model growth. A remarkable result of all experimental investigations and computer simulations is that the column tilt angle is always smaller than the incidence angle. Various explanations are known to explain this fact. These models will be presented and it will be shown that especially the competition model is able to describe a relation between the tilt angle and the angle of incidence for the complete range of material incidence angles. For various applications, patterning of the substrate prior to growth is required to fabricate arrays for highly regular nanostructures. This fabrication is demonstrated and the application of these structures for the realization of biosensors and magnetic nanotubes is shown.