X-RAY STUDY OF THE WETTING BEHAVIOR OF CCL4 ON SI/SIO2 SURFACES

The complete wetting of an uncoated silicon wafer covered with a native oxide layer by saturated vapour of carbon tetrachloride was studied by using the x-ray reflectivity-technique. Differential heating of the substrate relative to a liquid reservoir was used to examine the disjoining pressure as a function of film thickness. The measurements were done at the temperatures T=308K and T=318K of the reservoir. The observed film thicknesses varied between 26angstrom and 345angstrom depending on the temperature difference. A model for explaining the measured film thickness as a function of the temperature difference in terms of van der Waals forces is presented. It is based on the non-retarded interaction and includes terms of higher order in the film thickness. Microscopic constants like the Hamaker constant were determined and compared with reported values.