Exploitable results Methods of measuring the relative plasma composition by active charge exchange 2 methods of measuring the hydrogenic composition of a plasma with an active diagnostic beam have been investigated: evaluation at equal energies of the neutrals leaving the plasma and at equal velocities. Evaluation at equal velocity has the advantage that the plasma composition, particle penetration and stripping efficiency of the analyser do not enter the evaluation. The only plasma parameter that has to be known is the plasma temperature. If measurement at 2 different velocities is possible, the temperature can also be evaluated from the corresponding 4 fluxes without any further knowledge of plasma or beam parameters. The circumstances under which evaluation of the plasma composition for non-Maxwellian distribution functions is possible have been studied. As the halo effect may be the main source of error, the application of a helium beam may reduce this problem considerably. Ion scattering analysis of rhodium adlayers on alumina films Rhodium shows catalytic activities for a variety of chemical reactions. Its flexibility, as regards reactivity in carbon monoxide hydrogenation, makes it very interesting for the examination of catalytic mechanisms. Moreover, rhodium and other group VIII metals have been found to show strong interactions between the metal and typically reducible oxidic supports such as titanium dioxide (SMSI, strong metal support interactions). Similar effects have also been reported with non-reducible supports such as alumina. To study systems with surface sensitive methods using charged particles, it is convenient or even necessary that the samples show sufficient electrical conductivity. In this work, thin oxide films prepared by anodic oxidation of aluminium exhibited no disturbing charging effects. Model systems for rhodium/alumina catalysts with metal loadings of one monolayer were prepared and characterised by Ion Scattering Spectroscopy (ISS) and Rutherford Backscattering Spectroscopy (RBS). It was shown that alumina layers up to some hundred angstroms thick have a sufficiently high electrical conductivity to be examined with ion beam methods. The surface of the anodically prepared oxide films is much larger than the geometric area of the specimen. Their thickness can be increased by calcination of the samples. The distribution of oxygen in the calcined alumina layer is inhomogeneous, the stoichiometry changing continuously from alumina to metallic aluminium with increasing depth. The metal was uniformly distributed over the samples, and no indication of clustering or island formation was found. Due to the large oxide surface, the rhodium does not cover the support completely. Effect of ion energy on film deposition Electron cyclotron resonance (ECR) excited plasmas are especially useful for processes requiring low pressure and low gas temperature, and for the deposition of insulating layers. In this case ECR plasma is generated by coupling a circularly polarized microwave (2.45 GHz) into the reaction chamber. Resonance with the electrons gyrating in the overlying magnetic field at 87.5 mT leads to an acceleration of the electrons, which in turn ionize the processing gas. For the deposition of hydrocarbon and polymerin like hydrocarbon films it has been shown that the impact energy of ions on the substrate has a decisive effect on microstructure and macroscopic properties of the deposited films. The possible control of ion energies by varying the magnetic field configuration makes the ECR plasmas attractive for methane film deposition altering the film properties. In order to investigate this relationship an ion energy analyzer was introduced into the reaction chamber in place of the substrate. Ion energy distributions in carbon and methane under various discharge conditions were measured. Searching for OpenAIRE data... There was an error trying to search data from OpenAIRE No results available
