A Comparison Between X-ray Reflectivity and Atomic Force Microscopy on the Characterization of a Surface Roughness

摘要

X-ray reflectivity and atomic force microscopy are two complementary tools in characterizing the surface morphology of a solid sample. However, the measured results reported by these two methods were usually not consistent. To understand this inconsistency, a possible interpretation for X-ray reflectivity and atomic force microscopy on the surface characterization of a solid sample is described. The difference in these two methods is the X-ray beam covers a larger area of few mm~(2) on the sample surface while the atomic force microscopy probes only a local area (around (mu)m~(2)). The lateral resolution of X-ray reflectivity is about 0.1 nm depending on the wavelength of the X-ray source and while the AFM is limited by the dimension of the tip. In general, the surface roughness measured by AFM should be smoother than that obtained by X-ray reflectivity. However, the surface contamination complicates the measurements for both methods, especially, for these samples with roughness less than 1 nm.