Ion beam mixing

Ion beam mixing

A process in which bombardment of a solid with a beam of energetic ions causes the intermixing of the atoms of two separate phases originally present in the near-surface region. In the well-established process of ion implantation, the ions are incident instead on a homogeneous solid, into which they are incorporated over a range of depths determined by their initial energy. In the simplest example of ion beam mixing, the solid is a composite consisting of a substrate and a thin film of a different material (illus. a). Ions with sufficient energy pass through the film into the substrate, and this causes mixing of the film and substrate atoms (illus. b). If the ion dose is large enough, the original film will completely disappear (illus. c). This process may result in the impurity doping of the substrate, in the formation of an alloy or two-phase mixture, or in the production of a stable or metastable solid phase that is different from either the film or the substrate. See Ion implantation

Like ion implantation, ion beam mixing is a solid-state process that permits controlled change in the composition and properties of the near-surface region of solids. Although not yet employed commercially, it is expected to be useful for such applications as the surface modification of metals and semiconductor device processing. In conjunction with thin-film deposition technology, ion beam mixing should make it possible to introduce many impurity elements at concentrations too high for ion implantation to be practical.