0000000000161221
AUTHOR
R. Ohr
Soft X-ray photoelectron microscopy used for the characterization of diamond, a-C and CN , thin films
Abstract This article gives an overview about the application of X-ray photoemission electron microscopy (X-PEEM) used for the analysis of carbon thin films. We present the results of an X-ray absorption near edge structure (XANES) study of CVD diamond, a-C and CNx films on Si (100) as well as a defect analysis of a hard disc scratch test. The sp2/sp3 ratio of the carbon films was determined and mapped in the electron micrographs, which show localized defects in the surface.
Investigations of the corrosion protection of ultrathin a-C and a-C:N overcoats for magnetic storage devices
Abstract The thickness-dependent corrosion protection of carbon overcoats for magnetic hard disks can be analyzed by collecting X-ray absorption near edge structure (XANES) spectra at the Co L3-edge. Co is the main constituent of the protected magnetic media underneath. The spectra of the Co absorption edge display a strong peak for pure metallic, non-oxidized Co. This peak splits up into several sub-structures for oxidized Co. Therefore, XANES spectra provide a straightforward method to determine the overcoat thickness, leading to closed coverage and corrosion protection of the underlying material. A similar approach was carried out by X-ray photoelectron spectroscopy (XPS). Standard a-C:N…
Resonant Raman characterisation of ultra-thin nano-protective carbon layers for magnetic storage devices
Abstract Carbon thin films are very important as protective coatings for a wide range of applications such as magnetic storage devices. The key parameter of interest is the sp3 fraction, since it controls the mechanical properties of the film. Visible Raman spectroscopy is a very popular technique to determine the carbon bonding. However, the visible Raman spectra mainly depend on the configuration and clustering of the sp2 sites. This can result in the Raman spectra of different samples looking similar albeit having a different structure. Thus, visible Raman alone cannot be used to derive the sp3 content. Here we monitor the carbon bonding by using a combined study of Raman spectra taken a…