Ion beam assisted deposition

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The ion beam-assisted deposition , and ion beam assisted deposition , ion beam assisted coating or ion beam assisted coating technique called ( English ion beam assisted deposition , IBAD ) is a coating method from the group of physical vapor deposition . It is primarily used for the production of thin layers . This is done through the deposition and simultaneous synthesis of metal atoms and gases on substrates . Metals are vaporized using different methods, gas molecules are dissociated and ionized by ion sources and, at the same time, offered to a mostly heated substrate surface. In contrast to most other deposition methods, in ion deposition with energetic ions from 10 eV up to 1000 eV the essential growth and phase formation processes take place a few nm below the surface of the growing layer. In this way, the process allows the structure , chemical properties and texturing of thin films or even coatings to be specifically influenced during the manufacturing process.

functionality

Analogous to molecular beam epitaxy , one or more metals are usually evaporated and additional reactive gases are dissociated or ionized or activated into atoms by various ion sources . IBAD systems consist on the one hand of a coating station, for example effusion cells , ion beam sputtering , magnetron sputtering , laser ablation or electron beam evaporator , which is responsible for the actual material deposition of the layer. In addition, different ion sources such as Kaufman ion sources , duoplasmatron , magnetron or atomic beam sources direct an ion or neutral particle beam at a suitable angle onto the growing film. The ions obtained in this way are accelerated to hyperthermal energies and have an additional pulse directed towards the substrate. As a result of the interaction of individual ions with the solid , order phenomena and structure formation processes occur, which can lead to the formation of certain metastable phases, the formation of amorphous or crystalline atomic agglomerates and, in some cases, the formation of textured layers. This allows the properties of layers and coatings to be manipulated, in particular with regard to intrinsic tension, adhesion , surface mechanical properties, corrosion and oxidation resistance as well as optical and electrical properties.

For example, IBAD offers the possibility of manipulating the orientation of the crystallites with the ion beam for some materials, i.e. to have a targeted influence on the biaxial texturing of the layer. A variation of the flow rate ratio between the layer-forming metal atoms and the ions extracted from the ion source allows the layer composition and the chemical phase ratio to be adjusted in a controlled manner. Analogous to molecular beam epitaxy , the high energy input of the ions (10–1000 eV) can significantly lower the substrate temperature compared to “normal” chemical vapor deposition . This means that a large number of different substrate materials (e.g. temperature-sensitive polymers or alloys ) can be coated using IBAD.

A disadvantage of this method, however, is precisely this high ion energy, which causes radiation damage in the layers, which in turn leads to a disruption of the crystallinity and has to be cured, for example, by suitable subsequent annealing .

See also

Individual evidence

  1. ^ B. Rauschenbach, JW Gerlach: Texture Development in Titanium Nitride Films Grown by Low-Energy Ion Assisted Deposition . In: Crystal Research and Technology . tape 35 , no. 6-7 , 2000, pp. 675-688 .
  2. ↑ JW Gerlach, D. Schrupp, R. Schwertberger, B. Rauschenbach, A. Anders: Study of Low-Energy Ion Assisted Epitaxy of GaN Films: Influence of the Initial Growth Rate . In: Mat. Res. Soc. Symp. Proc. tape 585 , 2000, pp. 239-244 .
  3. ↑ JW Gerlach, S. Sienz, W. Attenberger, B. Rauschenbach: Influence of defects in low-energy nitrogen ion beam assisted gallium nitride thin film deposition . In: Physica B: Physics of Condensed Matter . tape 308 , 2001, p. 81-84 .