Thin films were prepared on Cu substrates by using techniques such as direct-current sputtering, sol-gel and the microwave decomposition of SiH4 and O2. The sol-gel films were made by using a conventional mixture of tetraethoxysilane, water and ethanol. The O diffusion coefficient was deduced from the thickness of the copper oxide layer which was formed at the Cu/SiO2 interface; as estimated from reflectivity and Auger spectroscopy measurements. Heat treatment at various temperatures permitted the determination of the temperature dependence of the diffusion coefficient. It was found that the diffusion coefficient depended upon the method of preparation of the SiO2 layer. This was related to differences in the structure of the oxide layer. This was confirmed by dielectric breakdown measurements. It was concluded that the O diffusion constants and the dielectric breakdown field could be indicators of the structural quality of silica.

Oxygen Diffusion in Silicon Oxide Films Produced by Different Methods. J.J.Pérez-Bueno, R.Ramírez-Bon, Y.V.Vorobiev, F.Espinoza-Beltrán, J.González-Hernández: Thin Solid Films, 2000, 379[1-2], 57-63