Plasma diagnostics in a PVD triode ion plating installation

Abstract

In this thesis, two diagnostics tools are combined to relate the plasma process parameters in the triode ion plating system (BAI 640) to the film rnicrostructure of wear resistant coatings. The other topic, e.g. functionality, of the materials triangle is not investigated here. As diagnostics tools, the energy-resolved mass analyzer of Balzers (PPM 421) and self-constructed Langmuir probes are used. The PPM 421 detects ion fluxes from the whole plasma volume, with its highest sensitivity along the axis of the ion optics while the probe measures electron and ion fluxes in the proximity of the probe. It is important to know which ions and which neutrals, with bow much energy or speed, impinge on the surface of the substrates. An ion mass scan and a neutral mass scan, performed by the PPM 421 inserted next to the substrate table, can give information on the most important species, while the energy scan gives information on the energy distribution of these species. These so-called energy spectra of neutrals and ions are a convolution of different energy distributions. This indicates that there are potential hills in the plasma were the ions can accelerate. The fast neutrals mostly originate from a charge exchange collision with the ions. The Langmuir probe can help to locate the potential hills in the plasma. Moreover, a simple current-voltage measurement, performed by this type of collecting probe, can give the value of the plasma parameters with some reasonable accuracy. In combination with the results of the film microstructure, performed by X-ray diffraction, the process parameters of a deposition can be optimized to obtain films with controlled adhesion properties, friction protection and microhardness.