Structure zone models (Movchan-Demchishin, Thornton, etc.) have been proposed to predict the morphology of metal and metal-oxide films produced by PVD or CVD processes. An original model was proposed for metal-oxide coatings made by the sol-gel process, based on a thorough experimental study of the microstructure of many coatings either obtained at INM or reported by other laboratories. The different morphologies - granular, layered, columnar - were described in terms of a parameter q = ICS/SLT, where ICS is a so-called "intrinsic crystallite size" and SLT is the single layer thickness and the homologous temperature T-H = T-Sintering/T-Melting. The influence of these morphologies and parameters on the electrical properties of transparent conducting ZnO:Al coatings is reported. (c) 2005 Elsevier B.V. All rights reserved.