X-ray study of the wetting behaviour 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 temperaturesT=308K andT=318K of the reservoir. The observed film thicknesses varied between 26Å and 345Å 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.