This study examined the interfacial reactions between Cu clad laminate (CCL) substrates and atomic-layer-deposited (ALD) HfO2, Al2O3 and TiO2 films and their effects on the electrical properties of the films. The Cu and Pt substrates with similar to 150 nm thick sputtered Cu and Pt layers on SiO2/Si were also used as references. Serious interfacial reactions, such as defective CuOx interfacial layer growth and CuOx diffusion into the film, occurred in the ALD HfO2 films grown on the CCL substrates, which deteriorated electrical properties of the films. Although higher growth temperatures improved the properties of the ALD HfO2 film due to the lower concentrations of residual impurities in the films, the interfacial reactions became increasingly severe. Conversely the ALD Al2O3 films grown on the CCL substrates showed improved electrical properties as well as suppressed interfacial reactions and a sharp interface with the substrate compared to those of the ALD HfO2 films. This was confirmed by X-ray photoelectron spectroscopy analysis of ALD Al2O3, TiO2 and mixed oxide films. Effective interfacial reaction barrier properties of an ALD Al2O3 film were also demonstrated by an electrical examination of stacked films with Al2O3 and TiO2. (c) 2010 The Electrochemical Society. [DOI: 10.1149/1.3514601] All rights reserved.