Cerium oxide dielectric thin films have been grown on n-type silicon by atomic layer deposition using a monomeric homoleptic Ce-IV alkoxide precursor with water vapour. Herein we report the dielectric properties of CeO2 films deposited from tetrakis(1-methoxy-2-methyl-2-propanolate)cerium. The resulting films exhibit permittivities in the range 25-42 at 1 MHz with a strong dependency on the deposition temperature. The microstructural origin of this behaviour has been investigated. The as-deposited films were found to be crystalline and they exhibited the cubic fluorite structure for deposition temperatures in the range 150 degrees C to 350 degrees C. Variations in the crystallite sizes are governed by the deposition temperature and have been estimated using a Debye-Scherrer analysis of the X-ray diffraction patterns. The changing crystallite size correlates with changes seen in the triply-degenerate F-2g first-order Raman line half-width at 465 cm(-1). It is concluded that the frequency dependency of the film dielectric properties is strongly influenced by the crystallite size which in turn is governed by the growth temperature. (C) 2011 Elsevier B.V. All rights reserved.