Interfacial properties of thermally oxidized Ta2Si on Si

Many refractory metal silicides have received great attention due to their potential for innovative developments in the silicon‐based microelectronic industry. However, tantalum silicide, Ta2Si, has remained practically unnoticed since its successful application in silicon carbide technology as a simple route for a high‐k dielectric formation. The thermal oxidation of Ta2Si produces high‐k dielectric layers, (OTa2Si)‐based on a combination of Ta2O5 and SiO2. In this work, we investigate the interfacial properties of thermally oxidized (850–1050 °C) Ta2Si on commercial silicon substrates. The implications of diffusion processes in the dielectric properties of an oxidized layer are analyzed. In particular, we observe migration of tantalum pentoxide nanocrystals into the substrate with increasing oxidation temperature. An estimation of the insulator charge and interfacial OTa2Si/Si trap density is also presented. Copyright © 2008 John Wiley & Sons, Ltd.