Search

Abstract: Interaction of neutral hydrogen atoms with the layer of hydrogenated carbon–tungsten composite was studied. A 1μm thick layer was prepared by sputter deposition from C and WC-targets in Ar/C2–H2 gas mixture. After deposition the samples were treated in weakly ionized highly dissociated hydrogen plasma created in a microwave discharge at a power of 1kW. The gas flow was 13l/h and pressure was 90Pa. Temperature of the samples during treatment was about 850K. After plasma treatment the samples were analyzed by AES (Auger electron spectroscopy) depth profiling, XPS (X-ray photoelectron spectroscopy) and SEM (scanning electron microscopy). It was found that during hydrogen plasma treatment selective etching of the C–W layer occurred. Carbon was preferentially removed from the C–W layer, and after about 10min of treatment practically only tungsten with a huge porosity was detected. [Copyright &y& Elsevier]

Abstract: Metals can form several kinds of oxides. Iron forms wustite (FeO), magnetite (FeO+Fe2O3 or Fe3O4) and haematite (Fe2O3). Iron oxides, especially magnetite, are used for insulation between the lamellas of an electromotor made of electromagnetic sheet. In this work, iron oxide layers were characterized on industrial samples of electromagnetic sheet by AES depth profile analysis, and iron oxides with known chemical composition were used as reference samples, i.e. a magnetite mineral and a standard haematite reference sample. The magnetite mineral was chosen because it can be found in nature in a very pure form. The selection of reference samples was also verified on samples with an oxide layer of known composition, which were prepared by sputter deposition. The composition of the sputtered oxide layers was analysed by the weight-gain method and Rutherford backscattering without the use of standard reference materials (SRM), and the results were then compared with those obtained by AES depth profile analysis. [Copyright &y& Elsevier]

Abstract: Focused ion beam (FIB)-induced ion mixing was studied in a C/Si/C/Si/C/Si substrate multilayer structure sample by means of Auger electron spectroscopy (AES) depth profiling, and transmission electron microscopy (TEM). The multilayer sample was irradiated with Ga+ ions using focused ion beam (FIB) at room temperature. The ion energy and fluence of the ion irradiation varied in the range of 10–30keV and 10–120×1015 ions/cm2, respectively. The ion irradiation induced a slightly asymmetric intermixing of the top C and Si layers, which could be modeled by the TRIDYN code. During ion mixing, part of the intermixed C and Si atoms reacted, forming amorphous SiC. The amount of SiC depends on the square root of the Ga+ fluence. Thus, amorphous SiC thin film (with Ga contamination) with thickness in the nanometer range can be produced by means of FIB. [Copyright &y& Elsevier]