Ultra thin films of ZrO2 were synthesized on soda lime glass and SnO2-coated glass, using ZrCl4 and H2O precursors by atomic layer deposition (ALD), a sequential CVD technique allowing the formation of dense and homogeneous films. The effect of temperature on the film growth kinetics shows a first temperature window for ALD processing between 280 and 350 degreesC and a second regime or "pseudo-window" between 380 and 400 degreesC, with a growth speed of about one monolayer per cycle. The structure and morphology of films of less than I mum were characterized by XRD and SEM. From 275 degreesC, the ZrO2 film is crystallized in a tetragonal form while a mixture of tetragonal and monoclinic phases appears at 375 degreesC. Impedance spectroscopy measurements confirmed the electrical properties of ZrO2 and the very low porosity of the deposited layer. (C) 2002 Elsevier Science B.V. All rights reserved.