Figure 39.8: Schematic diagram of the Ion Beam Sputtering system using a Si target and O2, N2 discharges.
(5) Ion Beam sputtering technique:
Figure 39.8 shows the typical set up of Ion beam sputtering [5]. In this method, a separate ion source is kept for the generation of energetic particles, where the ion flux and ion energy can be controlled independently and the angle of incidence on the target can be optimized with respect to a maximal sputter yield. With dual beam ion sources the film growth can be influenced additionally by the bombardment with energetic particles of a defined energy and angle of incidence, frequently used for activated reactive sputtering or for the production of highly textured films by selective resputtering of misoriented crystallites.
In comparison to sputtering processes, ion beam sputtering offers a variety of advantages: (1) A low working gas pressure in combination with the absence of interactions between the substrates and the plasma result in high-quality thin films with mimimum contamination and defects, (ii) Ion beam sputtering is extremely stable process, which allows for a high degree of automation. Nevertheless, ion beam sputtering is less often used in the industrial mass production due to economic disadvantages: low deposition rate (10 times lower than sputtering techniques) and technical difficulty in coating large areas uniformly.