A five-layer model for low-emissivity (Low-E) coated glass with SnO2:F/SiCxOy tandem thin films has been developed for spectroscopic ellipsometry (SE) measurement. A comprehensive interpretation of this structure model is also presented. The theoretical, optical, and structural parameters obtained by fitting the SE experimental data have been proven credible using other auxiliary measurements, including spectrophotometry, atomic force microscopy, scanning electronic microscopy and transmission electronic microscopy. The effect of the diffusing sodium ions on the optical and electronic properties of the film is also discussed. These results demonstrate that SE, accompanied with this five-layer model, is helpful for an on-line characterization of the Low-E coating process used as a non-destructive and low time-consuming method. (C) 2013 Elsevier B.V. All rights reserved.