Study of the surfaces of CVD-WO3 films, by atomic force microscopy and spectroscopic ellipsometry

Atomic force microscopy imaging of chemical vapor deposition WO3 films reveals the presence of domed crystallites that resemble the florets of cauliflowers with a rough surface texture. Annealing at 400degreesC and above leads to further surface roughening, with estimated root mean square roughness values of 40-50 nm. Spectroscopic ellipsometry analysis shows that the surface layer becomes thicker with increasing oxygen flow rate during film deposition. This layer is predominantly amorphous for as-deposited films, and predominantly crystalline after annealing. (C) 2003 Kluwer Academic Publishers