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Plasma Immersion Ion Implantation (PIII)The research area of plasma immersion ion implantation encompasses the modification of surfaces with energetic ions as well as the characterisation of the plasma and the plasma sheath, from where the ions are originating. Additionally, a materials laboratory is maintained for mechanical testing and characterisation of the surfaces. Thus, the complete process chain is covered. The method is additionally used for the formation of biocompatible surfaces. Plasma immersion ion implantation (PIII) has been established during the last 20 years as method which allows the homogeneous implantation into arbitrarily complex shaped objects (cf. Fig. 1), thus circumventing the “line-of-sight” restriction of conventional ion implantation. In a pulsed mode, a very high ion current is extracted from the plasma. From the viewpoint of fundamental research, the interaction of a supersonic plasma stream, resulting in a highly inhomogeneous plasma density, with the high voltage pulses needs further investigations, especially concerning the temporal and energetic distribution of implanted ions. Information obtained here is furthermore used for custom-designed system development.
The impact of energetic ions on a surface results in the sputtering of atoms from the solid and in the energy deposition through collision cascades in the solid. This athermal energy allows phase formation and segregation processes far away from thermal equilibrium (see Fig. 3). Implantation at elevated temperatures allows thermal diffusion processes and the formation of thick functional layers. Furthermore, the implanted region is characterised by compressive stress due to the additional atoms, which may leads to plastic flow of the surface material. Sputtering is partially related with stress removal and leads to an additional modification of the surface topology, i.e. smoothing, roughening or nanostructuring. When determining the surface properties of such modified materials, surface physic methods complement modern tools for materials testing.
Beside PIII, low energy broadbeam ion sources (cf. Fig. 4) are used in addition to conventional ion implantation.
The present work encompasses the range from fundamental investigations to development of specific applications in the following areas:
Selected Publications
Contact
PD Dr. Stephan Mändl
Horst Neumann Related Articles
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