AVS 49th International Symposium
    Applied Surface Science Tuesday Sessions
       Session AS-TuP

Paper AS-TuP3
Compensating for the Ubiquitous Hydrocarbon Overlayer to Enable Quantification of the Elemental Composition from XPS; the Air-formed Film at the Aluminium Surface

Tuesday, November 5, 2002, 5:30 pm, Room Exhibit Hall B2

Session: Topics in Applied Surface Science
Presenter: X. Zhou, UMIST, UK
Authors: M.R. Alexander, UMIST, UK
G.E. Thompson, UMIST, UK
X. Zhou, UMIST, UK
G. Beamson, Daresbury Laboratories, UK
Correspondent: Click to Email
Air-formed and anodic films at the surface of aluminium are of considerable technological importance. The chemistry of the surface is relevant to the performance of coated and bonded aluminium; XPS is a powerful tool in characterising this surface.@footnote 1@ Unfortunately, when an overlayer of hydrocarbon contamination is present on the air-formed oxide film, quantification of the elemental composition using XPS requires a correction to account for the greater attenuation of lower KE photoelectrons. Different methods have been developed to correct for this effect that do not require etching or angle resolved measurements. These include the Ebel model and modifications of this approach,@footnote 2@ the Evans approach@footnote 3@ and the Vereecke and Rouxhet method.@footnote 4@ Application of these methods is compared for a range of overlayer thickness using a plasma polymerised hexane coating (ppHex) as a model for hydrocarbon contamination. The thickness was measured using in situ quartz crystal microbalance, XPS signal attenuation and TEM. A stable and reproducible hydrothermally-formed pseudoboehmite (AlOOH) sample is used with hydrocarbon contamination as low as [C]=1 at%.@footnote 5@ Application to relevant systems is considered. @FootnoteText@ @footnote 1@ M. R. ALEXANDER, G. E. THOMPSON and G. BEAMSON, Surface and Interface Analysis 29 (2000) 468. @footnote 2@ M. EBEL, M. SCHMID and A. VOGEL, J Electron Spectroscopy and Related Phenomena 34 (1984) 313. @footnote 3@ S. EVANS, Surface and Interface Analysis 25 (1997) 924. @footnote 4@ G. VEREECKE and P. ROUXHET, Surface and Interface Analysis 27 (1999) 761. @footnote 5@ M. R. ALEXANDER, S. PAYAN and T. M. DUC, Surface and Interface Analysis 26 (1998) 961.